H. 



PLESIOPEXErS. 



AEIST.EOPSIS. 



HEPOJUDUS. 



ABIST.EOJIOBPHA. 



Cerricsil groove fine but conspicuous : tlie plenro- 

 branchiae in advance of somite siv, tliough small 

 and slender, are plumose ... ... ... HEMIPE- 



2. The third pair of thoracic legs have an epipodite and a podo- 

 brancb, the 4th pair have an epipodite : 



i. Exopodite of tlie 2nd pair of maxillipeds stiff as in 

 Peneut, much longer than the endopodite : plenro- 

 branchise small and slender but plumose 

 ii. Exopodite of tlie 2nd pair of maxillipeds slender and 

 lax, shorter even thnn the mems-joint of the 

 endopodite : plenrobranchise quite large 

 I. An hepatic spine : 



1. The third pair of thoracic legs have an epipodite, bnfc no 



podobranch, the 4th pair have no epipodite 



2. The third pair of thoracic legs have an epipodite and a podo- 



branch, the 4th pair have an epipodite : the rostrum is 

 many-toothed 



Subgenus ABIST.EU?. 



Arittm*, DuTemoy, lot. cit. : Wood-Mason (part) Ice. cit. 

 Eemipenaeuf, Spence Bate (part) Challenger Crustacea ilacmra, p. 299. 



Kostrum 3-toothed, very long in the female, of moderate length in the male. 

 Cervical groove indistinct. Two spines on either side of the carapace one 

 behind the base of the antennule, the other behind the base of the antenna : 

 no hepatic spine. 



Last 3 abdominal terga carinated, the carina in each ending in a spine. 



Terminal joint of the mandibular palp triangular. Exopodite of the 2nd 

 pair of maxillipeds slender, subcylindrical, lax, very little longer than the 

 endopodite. Dactyli of the last 2 pairs of legs setiform. 



There is no podobranch to the 3rd pair of thoracic legs, and no epipodite 

 to the fourth. The pleurobranchiae of the somites from the 8th to the 13th are 

 truly rudimentary, being either papilla? or small naked filaments, or at most 

 small filaments with three or four tiny pinnules. 



The branchial formula is as follows : 



Total 



4 + 6 ep. 



G+r. 



ep. 



