60 THE VOYAGE OF H.M.S. CHALLENGER. 



rather large, discoidal, with retractile processes. Pedicels about twenty-six, thirteen 

 along each side of the ventral surface. The anterior part of the dorsal surface bearing 

 some small processes. Integument thin, soft, and transparent, with three sorts of cal- 

 careous deposits : numerous three-armed, spinose bodies, each arm with two opposite, 

 very spinose processes ; a few spinose unbranched spicula, and small scattered wheels, 

 with twelve spokes. 



Colour in alcohol, white. Length, about 40 mm. Breadth, about 20 to 25 mm. 



Habitat.— Station 147. December 30, 1873. Lat. 46° 16' S., long. 48° 27' E. 

 Depth, 1600 fathoms ; bottom temperature, 0'8° C, globigerina ooze. Four specimens. 



All the four specimens being very contracted, it is difficult to determine their size 

 or true shape, which however seem to agree with those usual in the genus Elpidia. 

 The ventral surface is more or less flat, the dorsal, on the contrary, is extremely convex. 

 The body is nearly evenly rounded towards its extremities. The number of tentacles 

 varies from eleven to twelve, and their size does not seem to be constantly equal, two 

 of the dorsal ones being rather rudimentary in one individual. Their terminal part bears 

 processes, those round the edge being largest. Two of the animals carry twenty-six 

 closely crowded pedicels, and probably the number on the other two is the same, though 

 I have not been able to determine it. From the state of contraction of the body, it is 

 impossible to form any correct idea of the dorsal processes ; it seems, however, that some 

 small ones project anteriorly, close to the tentacles. The three-armed deposits (PL 

 XXXII. figs. 21-23) vary greatly in size, the arms of the largest ones measuring about 

 0'22 mm. in length ; each arm carries at some distance from the common centre two very 

 spinose processes. The deposits of the ventral surface are smaller and more scattered, 

 have a more irregular shape, and give off considerably smaller processes ; besides those, a 

 few spinose unbranched spicula are to be found. The wheels, which are scattered over 

 the dorsal as well as the ventral surface, measure about 0*06 mm .in diameter, and are 

 provided with twelve spokes ; between each of those the felly gives off a rounded process 

 or lobe, directed obliquely outwards. The nave is large, and sends out from its middle a 

 small irregular crown, consisting of four slightly curved rods united with each other. 

 The pedicels contain some straight and curved, spinose or smooth, spicula of greater or 

 smaller size. The tentacles have also some spicula, which seem to bear one or several 

 branches. The calcareous ring seems to resemble that of Parelpidia clongata; each of 

 its five pieces gives off about twenty-four diverging rods, their ends being flattened 

 and dilated. Only a single polian vesicle is present, measuring about 8 mm. in 

 length. 



Family II. Deimatid^e. 



Body usually rather long, cylindrical or fusiform, seldom shorter and of an elliptical 

 form. Tentacles fifteen or twenty. Mouth almost temiinal, though more or less 



