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



This animal bears so strong a resemblance to Benthodytes sanguinolenta that I am 

 undecided as to whether I am authorised in referring it to a variety or not. The 

 characteristics which distinguish them from one another seem to be of very bttle import- 

 ance. The specimens at my disposal are, however, in such a state of maceration and 

 incompleteness as to make a closer examination impossible, all traces of calcareous matter 

 being completely dissolved. The largest specimen reaches a length of 2G0 to 270 mm. 

 and a breadth of about 40 to 45 mm. In some individuals the brim round the body 

 is much more considerable and distinct than in others. The head-part of the body is 

 rather depressed. The large discoidal terminal part of the tentacles as well as its retrac- 

 tile processes are covered with small papilla? ; three to four of the ventral tentacles are 

 considerably smaller than the others. The odd ambulacrum is provided with about a 

 hundred small cylindrical pedicels ; its foremost and hindmost parts however have none. 

 The papilla-like prominences or pedicels round the brim are minute, and estimated in 

 number at about two hundred in all ; the canals which connect them with the ambulacra! 

 system are wide, and are plainly visible in consequence of their walls being full of a dark 

 pigment (PI. XL. fig. 8). The dorsal ambulacra give off a great abundance of longer and 

 shorter canals which run into a corresponding number of minute thread-like completely 

 retractile processes (PL XL. fig. 6) ; these processes are scattered all over the lateral inter- 

 ambulacra and also over those parts of the odd interambulacrum which border on both of 

 the dorsal ambulacra. The integument is very much macerated, and presents only very 

 indistinct traces of four-armed deposits, of which the calcareous substances have been 

 almost entirely dissolved. The pedicels and tentacles are strengthened by small trans- 

 verse spicula. The colour is light grey inclining to blue or violet ; the tentacles as well 

 as the integument surrounding the mouth and along the middle of the ventral surface 

 are of a dark violet almost black. All the interior organs closely resemble those of 

 Benthodytes sanguinolenta, excepting the reproductive organ, which is smaller, from 110 

 to 120 mm. in length in the largest specimens, and much thinner; each of its fascicles 

 is composed of a long, wide canal carrying a small number of thin bundles of caeca, which 

 are long and thread-like in the females and oval and much shorter in the males. 



Benthodytes abyssicola, n. sp. 



Body elongated, almost cylindrical, six to seven times as long as broad. Tentacles 

 fifteen, with their large discoidal terminal part provided with about twelve digitiform 

 retractile processes round its edge. Each of the dorsal ambulacra with about eight to ten 

 minute scattered processes. Integument rather thin and pliable, with scattered, cruciform 

 calcareous deposits, the calcareous substances of which are completely dissolved. 



Colour in alcohol blackish- or brownish-violet, here and there considerably lighter ; in 

 some individuals the coloration is uniform, light dirty violet. Length, about 280 mm. 

 Breadth, about 40 mm. 



