1886.] DURING THE VOYAGE OF H.M.S. 'CHALLENGER.' 119 



Genus Paratanais, Dana. 



1. Paratanais bathybrotis, n, sp. 



The single specimen measures 4 millim. The cephalothoracic 

 shield is about as long as the following two segments of the thorax ; 

 it is prolonged anteriorly into a wide obtusely pointed rostrum. Eyes 

 are present and well developed. The first segment of the thorax is 

 rather shorter than the rest, which are subequal. The length of the 

 abdomen is about one fourth of that of the entire body. The 

 antennules have a very characteristic form ; they are composed of 

 four joints ; the basal joint is as long as the rest of the appendage, 

 and is extremely wide and flattened ; the following joint is short and 

 wide ; the third joint is no longer, but is narrower; the terminal joint, 

 which represents the flagellum, is short and conical in form. The 

 antennae are shorter than the antennules, but, like them, consist of 

 four joints ; the first joint is wide and flattened, the second joint has 

 the same shape, but is shorter, the third joint is narrow and cylin- 

 drical ; the distal joint is short and narrows towards its termination. 



Station 246 ; 2050 fathoms. 



2. Paratanais dimorphus, n. sp. 



A very considerable number of individuals of a small species of 

 Paratanais were dredged in shallow water at Kerguelen, which are to 

 be distinguished by a very pronounced sexual dimorphism. The 

 female is like many other species of the genus ; but the male is 

 remarkable on account of the more slender body and the great 

 difference in the structure of the chelipeds. Both males and females 

 measure, in most cases, 3 mm. in length. In the male the cephalo- 

 thorax is rather long and narrow, and equals in length the first three 

 segments of the body together with half of the fourth ; the first free 

 segment of the thorax is the shortest; the second is twice the 

 length of the first ; the third segment is half as long again as the 

 second ; the fourth and fifth are subequal and about half as long 

 again as the third ; the last segment is about equal in length to the 

 third. The abdomen equals in length the last two thoracic segments. 

 The antennules consist of five joints ; the antennce of six. In the 

 female the antennary organs are shorter, the antennules being three- 

 jointed and the antennae five. The chelipeds are long ; both the 

 moveable and the fixed ' finger ' are of great length ; the latter is, 

 however, not as in other Tanaids a mere prolongation of the penulti- 

 mate joint, but is freely moveable, being articulated with it. In the 

 female the chelipeds are quite normal in structure. The uropoda 

 are biramose, each ramus being two-jointed. 



Kerguelen, Christmas Harbour, 120 fathoms. 



Fam. An c Ei D^. 

 Genus Anceus (Praniza), Risso. 

 1. Anceus bathybius, n. sp. 



Only a single fragment of this species was obtained from deep- 

 water ; the abdomen was entirely wanting. The specimen is a male 



