| OCR Text |
Show 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 antenna? 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 cylindrical ; 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 m m . in length. In the male the cephalothorax 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 antennae 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 penultimate 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. ANCEIDJ:. 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 |
