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



about seven along each side. Integument with two sorts of calcareous deposits ; four 

 armed bodies with four processes resembling those of Elpidia purpurea ; and small 

 wheels with eight or ten spokes. 



Colour in alcohol, light violet. Leugth, about 35 mm. Breadth, about 15 mm. 



Habitat. — Station 157. March 3, 1874. Lat. 53° 55' S., long. 108° 35' E. 

 Depth, 1950 fathoms ; diatom ooze. Two incomplete specimens. 



The two individuals obtained from the above station are in such an incomplete state, 

 that the description of them cannot be otherwise than very unsatisfactory. The form of 

 the body it is almost impossible to state. All along each side of the body the perisoma 

 forms a distinct list or brim, which may, however, depend on the contraction iu alcohol. 

 The terminal part of the tentacles bears a number of small retractile processes, of which 

 two on its outer margin are largest ; all these processes are, in their turn, provided with a 

 number of very small retractile papilliform projections. Among the dorsal processes the 

 first pair, situated on the anterior extremity of the body, is of considerable length, about 

 17 mm. ; the pair placed immediately behind is very inconsiderable, and the processes 

 arising close behind this second pair, one or two on each ambulacrum, are completely 

 rudimentary, almost invisible. Pedicels are only to be observed round the posterior half of 

 the ventral surface, and most of them being torn off it is impossible to state correctly their 

 number ; they seem to have been about fourteen, seven along each side, and of a rather 

 considerable size. The calcareous deposits (PI. XXXIII. fig. 6) in the integument are, as 

 above remarked, of two sorts : four-armed bodies with four outwardly directed processes; 

 and very scattered small wheels, - 048 mm. in diameter, with eight to ten spokes, and 

 with four curved minute rods, proceeding from the inner margin of the nave and united 

 together in the centre. The four-armed deposits closely resemble those of Elpidia pur- 

 purea ; their size, however, as well as the proportions between the arms and the processes is 

 rather variable. The wheels are only to be found on the dorsal surface. The calcareous 

 deposits being scattered, the surface of the skin does not feel very rough. 



As may be seen, this species has a great resemblance to Elpidia purpurea, which, 

 however, differs by its darker colour, by the greater number of calcareous deposits, and 

 by its want of wheel-shaped bodies. 



Tabular View of the Species oftlie Genus Elpidia. 



I. Pedicels all along each side of the ventral surface. 



A. Body elongated, posteriorly depressed and flattened. 



a. Calcareous deposits : large four-armed bodies -with numerous 



long spines and spinose processes ; and smaller ones pro- 

 vided with two to four outwardly directed processes, . Elpidia loillemoesi. 



b. Calcareous deposits : only small four-armed bodies with two 



to four outwardly directed processes, . . . Elpidia incerta. 



