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



wyville-thomsoni, and this seems still more likely on considering the nature of the sea- 

 bottom and the comparatively inconsiderable depth where the animal was found living. 



The single specimen, obtained from Station 158, is distinguished by the strong 

 convexity of the dorsal surface, the height of the body being considerably greater than 

 the breadth, which may possibly be the result of contraction. 



The four individuals brought home by the Challenger expedition from Station 

 147 may possibly be regarded as " varieties." Their colour is darker than in the typical 

 form, and their tentacles are almost black. In one specimen the odd ambulacrum carries 

 posteriorly a couple of small pedicels. The genital process is inconsiderable. One indi- 

 vidual possesses a large cloaca which gives off a csecal prolongation towards the left side, 

 while another specimen has likewise a large cloaca but without any csecal prolongation. 

 In the two remaining individuals the posterior portion of the alimentary canal resembles 

 that of the typical form. The calcareous deposits of the ventral perisoma, especially the 

 spicula, are much more numerous, and the ends of the dorsal processes are strengthened 

 by a greater number of straight or arcuated spinose spicula, than is the case in the typical 

 form. 



Lcetmogone violacea, Theel (PI. XIII.). 



Lcetmogone violacea, Th^el, Preliminary Report on the HolothuricLT, p. 1 1 . 



Body elongated, about twice and a half as long as the greatest breadth. Mouth 

 anterior, subventral. Anus posterior, terminal, slightly dorsal. Tentacles of almost equal 

 size ; their terminal part rather large, almost discoidal, destitute of visible processes. 

 Pedicels eleven along the left side of the ventral surface, and twelve along the right, 

 rather long and large ; the posterior pairs small. Processes of the dorsal surface very 

 slender and flexible, in one individual twenty, in another twenty-three along each of the 

 ambulacra ; the largest process about as long as the greatest breadth of the body ; 

 a rather short genital process placed in the medio-dorsal line, a little behind the tentacles. 

 Integument very thin and rough, with four sorts of numerous calcareous deposits : 

 scattered spicula ; spinose bodies, cruciform or in the form of an X, with the four arms 

 curved ; large wheels frequently with eight spokes ; and small wheels, sometimes with 

 thirteen spokes. Both sorts of wheels resembling those of the preceding species ; 

 between the large and small wheels there are many forms, varying much in size and 

 shape. 



Colour in alcohol, grey violet. Ends of the tentacles light yellowish-brown. Length, 

 about 90 mm. Breadth, about 35 mm. 



Habitat.— Station 164. June 12,1874. Lat. 34° 8' S., long. 152° 0' E. Depth, 

 950 fathoms ; bottom temperature, 2"2° C. ; grey ooze. Two specimens. 



During the cruise of the " Knight Errant " between the Faroe Islands and the coast of 



