SCHIZOPODA. 471 



Fam. 1. Euphausiidae (Thysanopodidae*). Cuticle thin ; thoracic legs 

 bear gills and the last or last two pairs are generally vestigial. No 

 otolithic vesicle, but refracting luminiferous organs. Most species pela.gic. 



Sub-fam. 1. Euphausinae. Eyes not or only slightly bilobate ; 

 none of the legs much longer than their immediate fellows, nor ending 

 in brushes or claws ; palps of maxillae simple. Euphausia Dana, 

 7th and 8th legs vestigial ; Boreophausia Sars. B. inermis (Kroy.), 

 Arctic to English Channel. Thysanopoda M. Edw., only the 8th legs 

 vestigial, the 7th like the 6th. Nyctiplianes Sars, only the 8th legs 

 vestigial, the 6th and 7th without exopodites in female, peduncle of 

 1st antenna stouter in male than in female. N. norvegica M. Sars, 

 British and other seas. Meganyctiphanes Holt and Tattersall, only 

 the 8th leg vestigial, 6th and 7th with exopodites in both sexes, 

 peduncle of 1st antenna scarcely stouter in the males, f 



Sub-fam. 2. Nematoscelinae. Eyes more or less bilobate ; 

 2nd or 3rd legs elongated, ending in a brush or claw. Thysanoessa 

 Brandt, 2nd legs moderately elongated, last three gills two-branched. 

 Nematoscelis Sars, 2nd legs much elongated with terminal group of 

 spines, last five gills branched. Stylocheiron Sars, 3rd legs elongated, 

 with a more or less perfect chelate " hand," gills much reduced. 

 Nematobrachion Caiman, 3rd legs elongated, with a terminal group 

 of spines. 



Sub-fam. 3. Bentheuphausinae. Eyes imperfect, none of the legs 

 much longer than their fellows, palps of maxillae three-segmented. 

 Bentheuphausia Sars, without luminiferous organs. B. amblyops 

 Sars, abysses of Southern Ocean and Bay of Biscay. 



Tribe 2. HOLOTROPHA. 



First thoracic feet modified as maxillipeds, and bearing a simple bran- 

 chial epipodite. Posterior part of the dorsal shield only overlaps the 

 thoracic segments. Mandible with a lacinia mobilis. Heart tubular. 

 Young developed in a brood pouch and becoming free in the adult form. 



Fam. 1. Mysidae. Cuticle thin and transparent ; edges of the dorsal shield 

 not overlapping the base of the limbs ; thoracic legs (except the 1st) without 

 gills ; otolithic vesicle usually present in caudal appendage ; brood lamellae 

 usually confined to the two or three posterior thoracic legs. Abdominal 

 swimming feet vestigial in female. Mysis Latr., many species, one British; 

 Hemimysis Sars. ; Leptomysis Sars. The following 5 genera, closely allied to 

 Mysis, are indigenous in the brackish waters of the Caspian Sea : Paramy- 

 sis Czern. ; Metamysis Sars ; Mesomysis Czern. ; Katamysis Sars and Lim- 

 nomysis Czern. Austromysis Czern, occurs in the Mediterranean and the Cas- 

 pian. Podopsis Thomps. ; Amblyops Bars ; Pseudomma Sars, blind; Erythrops 

 Sars ; Hyper erythrops Holt and Tattersall ; Euchaetomera Sars ; Meterythrops 

 Smith ; Katerythrops, Paramblyops and Dactylerythrops Holt and Tattersall ; 

 Arachnomysis Chun ; Chunomysis Holt and Tattersall ; Brutomysis Chun ; 

 Parerythrops Sars ; Caesaromysis Ortmann ; Mysidopsis, Mysideis and 

 Mysidella Sars ; Heteromysis Smith, abdominal legs of male small as in 

 female. Littoral. Gastrosaccus Norm. ; Haplostylus Kossm. ; Anchialis 



* So named from the character of the branchiae (fli-o-acos, a tuft). 



f The genera named by Holt and Tattersall in this and the following 

 Tribe have been obtained by these authors from the Atlantic slope to the 

 W. of Ireland. 



