Idiomysis bumbumiensis sp. nov., a new mysid species (Mysida, Mysidae, Anisomysini) from Southeast Asia
expand article infoJa’afar Nurshazwan, Shozo Sawamoto§, Azman bin Abdul Rahim
‡ Universiti Kebangsaan Malaysia, Bangi, Malaysia
§ Unaffiliated, Shizuoka, Japan
Open Access


We provide a detailed description, including illustrations, of a new species of mysid belonging to the genus Idiomysis W. M. Tattersall, 1922 from Pulau Bum Bum, Sabah, Malaysia. The presence of two segments of antennal scale, a shorter endopod of uropod than the exopod and a pair of minute spines at the apex of the telson distinguishes Idiomysis bumbumiensis sp. nov. from all other species in the genus. The present species is the seventh member of the genus Idiomysis and it is the first described in Southeast Asia. It is also the third species of tribe Anisomysini discovered in Malaysian waters. We include an updated dichotomous key of all Idiomysis species.

Key Words

Pulau Bum Bum, Idiomysis, Malaysia, new species, Sabah


Mysids are considered as one of the most abundant and widely distributed crustaceans in the world, are known to inhabit all aquatic areas, but they are predominantly found in marine environments (Gan et al. 2010). Wittmann et al. (2014) established the tribe Anisomysini (former Mysini) for the first time, encompassing seven genera; Anisomysis Hansen, 1910; Carnegieomysis W. M. Tattersall, 1943; Halemysis Băcescu & Udrescu, 1984; Idiomysis W. M. Tattersall, 1922; Javanisomysis Băcescu, 1992, Mysidium Dana, 1852 and Paramesopodopsis Fenton, 1985. Today, six species of Idiomysis have been recorded from various locations. They include Idiomysis diadema Wittmann, 2016 from the coast of Dahab, Red Sea; Idiomysis inermis W. M. Tattersall, 1922 from Kilakarai, Gulf of Manaar, India; Idiomysis japonica Murano, 1978 from Nomo, Nagasaki, Japan; Idiomysis mozambicus Deprez, Wooldridge & Mees, 2001 from Nacala Bay, Mozambique, South Africa; Idiomysis robusta Connell, 2008 from the east coast of South Africa; and Idiomysis tsurnamali Băcescu, 1973 from Gulf of Elat, Red Sea. Some species (Idiomysis japonica, I. mozambica and I. robusta) are free-living by nature (Murano 1978; Deprez et al. 2001; Connell 2008), while some others (Idiomysis diadema, I. inermis and I. tsurnamali) associate with other organisms, such as sea anemones and sea urchins (Băcescu 1973; Greenwood and Hadley 1982; W. M. Tattersall 1922; Bhaduri and Crowther 2016; Wittmann 2016). Numerous species of mysids from the tribe Anisomysini have been discovered in Southeast Asian waters (Sawamoto 2014). To date, only two species, namely Anisomysis (Anisomysis) aikawai Ii, 1964 and A. (Paranisomysis) ohtsukai Murano, 1994, have been identified from Malaysian waters (Gan et al. 2010; Tan et al. 2014; Moriya 2016; Tan and Azman 2018) and there was no record of any mysid of the genus Idiomysis.

Pulau Bum Bum is situated in the Semporna District of southeast Sabah, an East Malaysian State. It is a constituent of the Sulu Sulawesi Marine Ecoregion (SSME) and Coral Triangle Initiative (CTI), making it one of the richest marine biodiversity territories in the world (Ho and Kassem 2009). The most recent discovery was the newly-described Cerapus bumbumiensis Nurshazwan, Ahmad-Zaki & Azman, 2020, collected from Pulau Bum Bum (Nurshazwan et al. 2020). Even though this location is well-known for its extraordinary marine life diversity, there is little information on reef-associated crustacean fauna, including mysids. The present study described and identified Idiomysis bumbumiensis sp. nov. as a new species from Pulau Bum Bum, Sabah, Malaysia.

Materials and methods

The specimens were collected using SCUBA diving equipment on a silty substrate near a large coral ledge of ND Divers House Reef, Pulau Bum Bum in Semporna, Sabah of East Malaysia (Fig. 1). Specimens were initially fixed with a 4% formaldehyde-seawater solution and subsequently preserved with 85% ethyl alcohol after sorting in the laboratory. The body length of the mysids was measured in the laboratory from the tip of the rostrum to the end of the telson, excluding apical spines. Appendages were dissected using a stereomicroscope (Olympus SZX9) and mounted on a temporary slide with a glycerol-ethanol mixed solution for illustrative purposes. An optical microscope (Olympus BX43), equipped with a camera lucida, visualised the images. They were then pencil-drawn and digitised in Adobe Illustrator CS6 following guidelines by Coleman (2003). The terminology used was according to Wittmann et al. (2014). All specimens were deposited in the Universiti Kebangsaan Malaysia Muzium Zoologi (UKMMZ), Bangi, Malaysia.

Figure 1. 

Map of Pulau Bum Bum, Semporna, Sabah, Malaysia



Idiomysis bumbumiensis sp. nov.

Figs 2, 3, 4, 5, 6

Type material

Holotype, adult male (BL. 2.3 mm, UKMMZ-1611); Allotype, ovigerous female (BL. 3.2 mm, UKMMZ-1612); Paratypes, two males (BL. 2.0 and 2.2 mm), one female (BL. 2.2 mm) (UKMMZ-1613); two females (BL. 2.6 and 3.1 mm, UKMMZ-1614), ND Divers House reef, Pulau Bum Bum, Semporna, Sabah, Malaysia, 4°26'43.2"N, 118°39'08.1"E, SCUBA diving, 29 November 2018, 10.5 m depth, collectors: Abu-Bakar A.Z., Azman B.A.R. and Dendy A.O.


Antennal scale 2-segmented, with short apical segment, scale without any spine; rostrum subtriangular with broad rounded apex; thoracic exopod 1–8 with 7–9 segments; thoracic endopod 1–2 robust, thoracic endopod 3–8 elongate; all pleopods longer than wide; fourth male pleopod with distinct exopod and endopod not separated by sutures at the base, exopod terminally with 1 large barbed seta (armed with a few setules); endopod of uropod shorter than exopod; telson with a pair of minute spines on terminal margin; telson length ratio to sixth abdominal somite is 0.8.

Description for male. Head and cephalic appendage

A pale-white and brownish body part (Fig. 2A, B). Orange to the yellowish-red cornea (Fig. 2A, B). Stout and bulky body (Figs 2A, 3A) due to slightly double-flexed pleon antero-dorsally; short carapace, exposed last three thoracic somites, upwards-pointed trapezoid-shaped wing-like extension (Fig. 3A); subtriangular shaped rostrum (Fig. 3B) with broad rounded apex (subtriangular and bluntly pointed) extending between eyes reaching a middle basal segment of antennule peduncle; very large eyes (Fig. 3B), globular; the cornea is wider than eyestalk, covering almost all of the eye surface.

Figure 2. 

Idiomysis bumbumiensis sp. nov. (freshly fixed), A. Lateral view of the holotype (BL. 2.3 mm, UKMMZ-1611); B. Lateral view of allotype (BL. 3.2 mm, UKMMZ-1612).

Antennule peduncle (Fig. 3D) with three segments; the basal segment is the longest with a ventral short lobe on subterminal position with three setae; the median segment is the shortest with a ventral short lobe on subterminal position with three setae; the terminal segment is almost 0.5 times as long as the first/basal segment, with eight setae and one plumose seta, hirsute appendix masculina present; inner flagellum with four segments; outer flagellum with 9–10 segments; aesthetascs present. Antennal peduncle (Fig. 3E) is very short and stout, with three segments; antennal scale is extending beyond antennule peduncle, long, robust and broad; suture present at 11–14% from apex; terminal segment with five plumose setae; proximal outer margin without plumose setae from the base of antennal scale is 64%, while proximal inner margin without plumose setae is 27%.

Figure 3. 

Idiomysis bumbumiensis sp. nov., holotype (BL. 2.3 mm, UKMMZ-1611). A. Habitus; B. Anterior body, dorsal view; C. Posterior body, dorsal view; D. Antennule, obliques dorso-lateral view; E. Antennal; F. Mandible; G. Maxilla; H. Maxillula. Scale bars equal 0.1 mm for D–E; 1 mm for A; 0.4 mm B–C; 0.05 mm for F–H.

Mandible (Fig. 3F) with incisor and molar process; well-developed lacinia mobilis; the molar process is present; palp with three segments; small basal segment without setae; median segment with eight setae along the outer (lateral) margin and three setae along inner (mesial) margin; terminal segment with six normal setae and four plumose setae. Normal maxilla (Fig. 3G) for the genus; exopod bearing five apical setae; two-segmented endopod, the sub-ellipsoidal shaped terminal segment with seven setae including two normal setae. Normal maxillula (Fig. 3H); basal lobe with nine large spines; precoxal lobe with two long setae and two small setae.


A round basal plate of thoracic exopod at both distal corners with 7–9 segments with the last 3–4 segments bearing 1–2 plumose setae; robust thoracopods 1–2, slender and elongated thoracopods 3–8; carpopropodus of thoracic endopod 1–8 with 2, 2, 2, 1–2, 3, 1–2, 1, 1 segments, but some segmental borders are not well distinct in thoracopods 3–8; smaller dactylus of thoracopods 3–8 than thoracopods 1–2; nail of thoracopods 3–8 is more slender compared to thoracopods 1–2. The first thoracopod epipod (Fig. 4A) is linguiform-subtriangular without seta; seven-segmented exopod, first four segments without seta, the fifth segment with one plumose seta, the sixth and seventh segments with two plumose setae; normal and robust endopod, densely setose along both lateral margins of the ischium to dactylus, each segment bearing 1–2 plumose setae; nail with a swollen base. Second thoracic exopod (Fig. 4B) with eight segments, last three segments with 1–2 plumose setae; robust thoracic endopod similar to the first thoracopod, but armed with lesser setae, from basis to dactylus bearing 1, 0, 2, 2, 6, 7 setae, respectively.

Figure 4. 

Idiomysis bumbumiensis sp. nov., holotype (BL. 2.3 mm, UKMMZ-1611). A. First thoracopod; B. Second thoracopod; C. Third thoracic endopod; D. Third thoracic exopod; E. Fourth thoracic endopod; F. Fifth thoracic endopod; G. Eighth thoracopod. Scale bars equal 0.1 mm for A–G.

Third thoracic exopod (Fig. 4C, D) with nine segments, the last four segments with 1–2 plumose setae; thoracic endopod is more slender and elongate instead of robust, two-segmented carpopropodus, all segments are armed with setae, dactylus is smaller than in thoracopods 1–2, the nail is more slender than first and second thoracopods. The fourth thoracic endopod (Fig. 4E) is similar to the third thoracopod, carpopropodus, with 1–2 segments. The fifth thoracic endopod (Fig. 4F) is slightly longer than in the fourth thoracopod, merus nearly equal in length to the preceding segment, three-segmented carpopropodus, elongated and slender nail. Eighth thoracic exopod (Fig. 4G) with seven segments; thoracic endopod is smaller and more slender than other thoracopods, merus is longer than the preceding segment, separate carpopropodus, short and small dactylus, the nail is shorter than other thoracopods.


Pleopods 1, 2, 3 and 5 (Fig. 5A, C, E) reduce to simple separate plates, each with 4–6 setae of different lengths, longer than width; length of pleopod is more than twice its width. Male pleopod 4 (Fig. 5D) has distinct endopod and exopod, both undivided and basally not separated by sutures; endopod with three plumose setae; exopod has one small terminal seta and a large-barbed seta (armed with a few setules).

Figure 5. 

Idiomysis bumbumiensis sp. nov., holotype (BL. 2.3 mm, UKMMZ-1611). A. Pleopod 1; B. Pleopod 2; C. Pleopod 3; D. Pleopod 4; E. Pleopod 5; F. Uropod; G. Telson. Scale bars equal 0.1 mm for A–G.

Uropod and telson

Uropod (Figs 3C, 5F) has a shorter endopod than exopod; both endopod and exopod have plumose setae all around, without setae on both margins of the proximal part of endopod and exopod; endopod with 14 plumose setae; exopod with 19 plumose setae; large statocyst (there are circular borders between ambitus versus tegmen and ambitus versus fundus). Telson (Figs 3C, 5G) is approximately 1.12 times longer than the width and 0.8 times longer than the sixth abdominal somite; short, subtriangular with rounded tip; extending halfway across statocyst of endopod; smooth margin, except for apex with a pair of minute spines.


Similar to male, except for the following differences: stouter and bulkier body (Fig. 6A) than male due to marsupium; marsupium of female on the eighth thoracopod is larger than seventh thoracopod, large with short setae along the distal margin. Antennule (Fig. 6B); inner flagellum with seven segments; outer flagellum with 12 segments; aesthetascs is present. Antennal scale (Fig. 6C) with suture present at 10%–14% from apex; from the base of antennal scale, 70% of the proximal outer margin is without plumose setae while 45% of the proximal inner margin is without plumose setae. Pleopod 4 (Fig. 6D) is similar to male pleopods 1–3, 5; longer than its width with six setae. Telson (Fig. 6E) is approximately 1.03 wider than its length; apex with a pair of minute spines.

Figure 6. 

Idiomysis bumbumiensis sp. nov., allotype (BL. 3.2 mm, UKMMZ-1612). A. Habitus; B. Antennule, oblique dorso-lateral view; C. Antennal; D. Pleopod 4; E. Telson. Scale bars equal 0.1 mm for B–E; 1 mm for A.


The specific epithet refers to the type locality; Pulau Bum Bum, Sabah, Borneo, Malaysia.

Colouration in freshly fixed specimens

(based on UKMMZ-1611, BL. 2.3 mm; UKMMZ-1612, BL. 3.2 mm; Fig. 2A, B). Zesty orange eyes. Antennal scale, carapace including thoracic and translucent abdominal somites with a combination of small orange, yellow and black patches.


The present species is the seventh member of the genus Idiomysis, but it is the first species of this genus to be described in Southeast Asia. It is also the third species of the tribe Anisomysini found in Malaysian waters besides Anisomysis (Anisomysis) aikawai Ii, 1964 and A. (Paranisomysis) ohtsukai Murano, 1994 (Moriya 2016; Tan and Azman 2018). The genus Idiomysis can be easily classified into two groups, based on the antennal scale; (i) entire or (ii) 2 segments. Idiomysis inermis, I. mozambica, I. robusta and I. tsurnamali are in the group of an entire antennal scale, while I. diadema and I. japonica are in the group of two-segmented antennal scale. The presence of the spine, which is exclusively in I. robusta, distinguishes the group with the entire antennal scale. The present new species, Idiomysis bumbumiensis sp. nov., has two antennal scale segments, similar to I. diadema and I. japonica. However, they can be differentiated by observing the apex of the telson. Both I. diadema and I. bumbumiensis sp. nov have a pair of minute apical spines exclusive to these two species; on the other hand, I. japonica has a bluntly rounded telson apex. The endopodal uropod in I. diadema shows a clear extension beyond the exopod, but this structure is shorter than the exopod in I. bumbumiensis.

Key to species of the genus Idiomysis (Based on males)

1 Not segmented antennal scale 2
Antennal scale with two segments 5
2 Broadly rounded rostrum 3
Triangular or subtriangular rostrum 4
3 Not segmented antennal scale, with spine I. robusta
Not segmented antennal scale, without spine I. inermis
4 Endopodal uropod is subequal to exopod I. mozambica
Endopodal uropod is clearly shorter than exopod I. tsurnamali
5 Bluntly rounded telson apex I. japonica
Telson apex with a pair of minute spines 6
6 Endopodal uropod clearly extends beyond exopod I. diadema
Endopodal uropod is shorter than exopod I. bumbumiensis sp. nov.


Idiomysis bumbumiensis sp. nov. is the sole representative of this genus in Southeast Asian waters. Idiomysis bumbumiensis sp. nov. was relatively abundant and easily found in the shallow water of lower than 15 m during night-sampling sessions (28 November 2018 and 29 November 2018). As they were directly collected using SCUBA diving equipment, supplementary information on their natural habitat and body colour is available. The recently described Cerapus bumbumiensis Nurshazwan, Ahmad-Zaki & Azman, 2020 was also observed in the accompanying fauna. Although one species of Idiomysis was categorically described in this paper, fellow macro-photographers discovered further evidence of at least two other distinctive species of Idiomysis in the vicinity.

Idiomysis lives either in a symbiotic relationship (Idiomysis diadema, I. inermis and I. tsurnamali) or free-living (I. japonica, I. mozambica and I. robusta). Idiomysis bumbumiensis is a free-living mysid that was found swimming in a swarm on the silty substrate. By comparing the body lengths of all the species of the genus Idiomysis, this new species is one of the smallest species, besides I. diadema. Another feature that distinguishes species within the genus Idiomysis is the length ratio between the telson and the last abdominal somite. As this feature has not been described for the six known species, the ratios are calculated, based on the original-drawn figures describing each species. The ratio is mostly 0.8–1.0, except for I. mozambicus, which has a ratio of 0.4. The ratio of the present species is 0.8. Thus, the telson of most Idiomysis species is estimated to be more than 4/5 times as long as the last abdominal somite, while I. mozambicus is 2/5 times as long as the last somite. As shown in Table 1, I. bumbumiensis sp. nov. can be distinguished from I. inermis and I. tsurnamali by several morphological features: two segments of antennal scale and a pair of minute spines on the apex of the telson. Table 1 shows a brief morphological variation from each species of the genus Idiomysis. More research would be required to uncover more underwater macrolife, particularly in this area known as the heart of the Coral Triangle. More unique and unidentified marine life would undoubtedly be discovered with the overwhelming support of local underwater photographers.

Table 1.

Morphological variation of seven species of the genus Idiomysis, including the new species.

Characters I. diadema Wittmann, 2016 I. inermis W. M. Tattersall, 1922 I. japonica Murano, 1978 I. mozambica Deprez, Wooldridge & Mees, 2001 I. robusta Connell, 2008 I. tsurnamali Băcescu, 1973 I. bumbumiensis sp. nov. (Present study)
Body length Male: 2.2–2.3 Male: 3.4–4.4 Male: 3.3 Male: 2.9–3.9 Male: 4.9–6.0 Male: 4.2–4.5 Male: 2.0–2.3
Female: 2.2–3.3 Female: 4.0–5.0 Female: 3.7–3.9 Female: 2.6–2.9 Female: 4.8–5.4 Female: 4.2–4.5 Female: 2.2–3.2
Rostrum Broadly rounded Broadly rounded Subtriangular (bluntly pointed) Subtriangular (bluntly pointed) Broadly rounded Triangular (pointed) Subtriangular (bluntly pointed)
Antennal scale Two segments (no spine) Entire (no spine) Two segments (no spine) Entire (no spine) Entire (spine) Entire (no spine) Two segments (no spine)
Segments of thoracic exopod 1–8 6–8 7–10 7–8 7–9 7–8 5–8 7–9
Male pleopod 4 exopod Single segment Single segment Single segment Two segments Single segment Single segment Single segment
Endopodal uropod Clearly extend beyond exopod Subequal to exopod Subequal to exopod Subequal to exopod Shorter than exopod Clearly shorter than exopod Shorter than exopod
Telson apex A pair of minute spines Bluntly rounded Bluntly rounded Bluntly rounded Bluntly rounded Bluntly rounded A pair of minute spines
Length ratio of fifth to sixth abdominal somite 0.5 0.5 0.5 0.4 0.4 0.5 0.6
Length ratio of telson to last abdominal somite 1.0 0.8–0.9 0.8 0.4 0.8 0.8 0.8
Distribution Coast of Sinai at Dahab, Red Sea Kilakarai, Gulf of Manaar & Moreton Bay, Australia Nagasaki, Japan Nacala Bay, Mozambique Park Rynie, East Coast of South Africa Gulf of Eilat, Red Sea Pulau Bum Bum, East Malaysia
Occurrence Swarms between spines of sea urchin Amongst weeds, sea anemone Near rocky bottom Near uneven rock and patches of sand Near sandy substrate, amongst rocks and low-profile reef Hovering over medusa or sea anemone Near coral ledge; silty substrate
Depth range 1–8 m 1–4 m 1–5 m 4 m 2–38 m 1–20 m 10–11 m


The authors are grateful to Mr A.Z. Abu-Bakar and A.O. Dendy for their assistance with field sampling. A special thank you to ND Divers for providing accommodation and Mr Lai Wei Zhong (Ocean Park Travel & Tour) for his invaluable assistance and logistics throughout the sampling process. Many thanks also go to the Ministry of Tourism, Arts and Culture (MOTAC) Sabah for organising the exploration under Voluntourism Bum-Bum Island Exploration Program in conjunction with Visit Malaysia Year 2020. We gratefully acknowledge Dr Luiz Felipe de Andrade, Dr Rofiza Yolanda, Dr Kay Van Damme and an anonymous reviewer for their thorough and constructive reviews on an earlier version of the manuscript. This work was supported by the Ministry of Education (Malaysia) under the Fundamental Research Grant Scheme (FRGS/1/2019/WAB13/ UKM/02/3).


  • Băcescu M (1973) A new case of commensalism in the Red Sea: The mysid Idiomysis tsurnamali n. sp. with the Coelenterata Megalactis and Cassiopea. Revue Roumaine de Biologie, Serie de Zoologie 18: 3–7.
  • Băcescu M (1992) Javanisomysis gutzui, n. sg., sp. n., mysidacé grégaire des eaux Indonésiennes. Revue Roumaine de Biologie: Série de Biologie Animale 37: 79–86.
  • Băcescu M, Udrescu A (1984) New data on the mysids from the South-Australian waters. The description of Halemysis australiensis gen. n., sp. n. Revue Roumaine de Biologie, Série de Biologie Animale 29: 93–98.
  • Bhaduri RN, Crowther AL (2016) Association of the mysid Idiomysis inermis with the sea anemone Stichodactyla haddoni in Moreton Bay, Australia. Marine Biodiversity 46: 707–711. h
  • Connell AD (2008) New species of mysids (Crustacea: Mysidae) from the east coast of South Africa, with notes on habitat preferences. African Natural History 4: 1–10.
  • Fenton GE (1985) Description of Paramesopodopsis rufa n.g. n.sp. from the coastal waters of Southern Tasmania. (Crustacea: Mysidacea). Hydrobiologia 122: 171–174.
  • Gan SY, Azman BAR, Yoshida T, Majid AM, Toda T, Takahashi K, Othman BHR (2010) Comparison of day and night mysid assemblages in a seagrass bed by using emergence traps, with key to species occurring at Pulau Tinggi, Malaysia. Coastal Marine Science 34: 74–81.
  • Greenwood JG, Hadley DJ (1982) A redescription of the mysid Idiomysis inermis W. M. Tattersall, 1922 (Mysidacea) to include the previously unknown female. Crustaceana 42: 174–178.
  • Ho N, Kassem K (2009) Reef Status of Semporna Priority Conservation Area. WWF-Malaysia, Kota Kinabalu, 24 pp.
  • Moriya M (2016) Study on the diversity of Mysidacea in Southeast Asia. PhD Thesis, University of Tokyo, Tokyo.
  • Murano M (1978) A new species of Idiomysis (Crustacea, Mysidacea) from Japan. Bulletin of National Science Museum, Series A (Zoology) 4: 263–266.
  • Nurshazwan J, Ahmad-Zaki A, Azman BAR (2020) A new species of Cerapus (Amphipoda: Senticaudata: Ischyroceridae) from Pulau Bum Bum, Sabah, Malaysia, with an identification key to Cerapus species. Zootaxa 4802: 519–533.
  • Tan HS, Azman BAR (2018) Diversity of coastal mysids from Pulau Tinggi, Sultan Iskandar Marine Park, Malaysia. Nauplius – The Journal of the Brazilian Crustacean Society 26: e2018037.
  • Tan HS, Azman BAR, Othman BHR (2014) Taxonomic status of mysid shrimps (Crustacea) from Peninsular Malaysia waters. Malayan Nature Journal 66: 103–116.
  • Tattersall WM (1922) Indian Mysidaceae. Records of the Indian Museum 24: 445–504.
  • Tattersall WM (1943) Biological results of last cruise of Carnegie IV. The mysids. In: Ault JP. Carnegie Institution Publications, Washington, No. 555: 61–72.
  • Wittmann KJ (2016) Description of Idiomysis diadema sp. nov. (Mysida, Mysidae, Anisomysini), associated with Diadema urchins in the Red Sea; with nomenclatorial notes on its genus. Crustaceana 89: 611–623.
  • Wittmann KJ, Ariani AP, Lagardère JP (2014) Orders Lophogastrida Boas, 1883, Stygiomysida Tchindonova, 1981, and Mysida Boas, 1883 (also known collectively as Mysidaceae). In: Von Vaupel, Klein JC, Charmantier-Daures M, Schram FR (Eds) Treatise on Zoology – Anatomy, Taxonomy, Biology. The Crustacea. Revised and Updated, as well as Extended from the Traité de Zoologie, 4 B. Brill, Leiden, 189–396.