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



efferent duct opens by a pore situated about 45 mm. behind the anterior extremity of 

 the body. In the male the fascicles are very thick and composed of numerous small, 

 oblong dichotomous cseca. The female fascicles, on the contrary, are veiy thin, each 

 made up of about three branches, which carry one or two unusually large, short and 

 thick, dichotomous csecal sacs. 



Benihodytes sordida, n. sp. (PI. XXIV.). 



Body elongated, slightly tapering towards the extremities, from three and a half to 

 five times as long as broad. Tentacles fifteen ; some of the ventral ones smaller than the 

 others ; their large discoidal terminal part with numerous retractile processes. Each of 

 the dorsal ambulacra with three rather large conical processes arranged in pairs, and 

 with some smaller ones. Integument soft and rather thin ; the calcareous deposits 

 completely dissolved. 



Colour in alcohol, dark greyish-brown inclining to blue or violet ; the back slightly 

 lighter. Length, about 280 mm. Breadth, about 60-80 mm. 



Habitat.— Station 156. February 26, 1874. Lat. 62° 26' S., long. 95° 44' E. 

 Depth, 1975 fathoms; diatom ooze. One individual. Station 157. March 3, 1874. 

 Lat. 53° 55' S., long. 108° 35' E. Depth, 1950 fathoms ; diatom ooze. Four incomplete 

 specimens. Station 158. March 7, 1874. Lat. 50° 1' S., long. 123° 4' E Depth, 

 1800 fathoms ; bottom temperature, 0*3° C. ; globigerina ooze. One specimen. Station 

 298. November 17, 1875. Lat, 34° 7' S., long. 73° 56' W. Depth, 2225 fathoms ; 

 bottom temperature, 1*3° C. ; grey mud. One specimen. 



The elongated body appears to reach its greatest width at the middle, and becomes gra- 

 dually depressed anteriorly and posteriorly. The dorsal surface is strongly convex, while 

 the ventral is slightly so or almost flat. Anteriorly the width of the body decreases, 

 so as to form a narrower neck-like portion immediately behind the considerably broader 

 round and flat head-part. The mouth is situated on the ventral surface in the centre of the 

 large discoidal head. Among the fifteen tentacles some of the ventral ones are slightly 

 smaller; their large, discoidal ends have a diameter of up to 12 mm. and carry numerous 

 retractile processes covered with some small papilke. The pedicels round the body, of 

 which the foremost ones belong to the dorsal ambulacra, while all the others communicate 

 with the lateral ventral ambulacra, present the aspect of larger and smaller protuberances 

 round the edge of the brim. The pedicels of the odd ambulacrum resemble minute 

 round warts with a diameter of about 3 mm. The three pairs of larger dorsal processes 

 are thus arranged : the first one at the first fourth of the body, the second in its middle, 

 and the third at the third fourth of the body. These processes attain a length of about 

 15 mm., and the circumference at their base is rather considerable. Besides these, some 

 minute processes are scattered over both of the ambulacra, the number of which I have 

 not been able to determine. 



