REPORT ON THE HOLOTHURIOIDEA. 69 



anus, minute. Processes of the lateral ambulacra of the ventral surface seven, almost 

 inflexible, and nearly as long as the greatest breadth of the body ; behind the anus a 

 rudimentary one. Processes of each of the dorsal ambulacra six to eight, resembling 

 the preceding in size and shape. Integument very thick and hard, with two kinds of 

 calcareous deposits : small branched spicula of various shape ; and larger and smaller, 

 irregularly rounded, perforated crowded plates, covering one another completely or with 

 their edges alone. 



Colour in alcohol, light grey. Length, about 165 mm. Breadth, about 95 mm. 



Habitat.— Station 246. July 2, 1875. Lat. 36° 10' N., long. 178° 0' E. Depth, 

 2050 fathoms ; bottom temperature, l - 3° C. ; grey ooze. Two specimens. 



The ventral surface is perfectly flat, while the dorsal one, on the contrary, is extremely 

 convex ; the anterior and posterior extremities of the body are almost evenly rounded. 

 The mouth and anus are situated cpiite on the ventral surface, the latter a little in front 

 of the hindmost pair of pedicels. The bilateral symmetry is particularly strongly marked 

 in this form, especially in regard to the external organs. The pedicels along one side of 

 the ventral surface correspond in number as well as in position and size with those of the 

 other side. The same seems to be the case with the processes, excepting those along the 

 dorsal ambulacra which are slightly variable, though the bilateral symmetry is still traceable 

 even there. The normal number of the dorsal processes seems to be eight along each 

 ambulacrum, though through deformity one or several processes may be wanting; thus 

 one individual possesses six processes along the left ambulacrum and eight along the 

 right, while another specimen has eight along the left ambulacrum and seven along 

 the right. The place where the absent process ought to have been is always plainly 

 indicated by the larger size of the interspace between the processes which hie in front 

 and behind. The pedicels in the middle of the body are larger than the others, 

 about 10 mm. in diameter at the base ; their top only is retractile. The processes 

 vary greatly in size, and attain sometimes a length approaching almost the greatest 

 breadth of the body ; their form is elongated conical and their base measures about 

 17 mm. in diameter. The tentacles (PI. XLIII. fig. 3) of this species as well as those 

 of Deima fastosum are very small in comparison with those of the other known forms, 

 and capable of being completely retracted, at the same time the whole crown may 

 be withdrawn, which is not the case in any other forms of the families Deimatidse 

 and ElpidiidsB. The individuals of the genus Deima which I have been able to 

 examine, all have the tentacles drawn into the body, and are thus no longer visible 

 externally. They are quite enclosed in an oral cavity which communicates with 

 the exterior by a small rounded aperture, placed in the centre of a more or less 

 circular disk, round the circumference of which are to be found numerous minute papilla?, 

 the importance of which I have pointed out in the anatomical part of the report. 

 On account of the retracted state of the tentacles it is impossible to determine whether 



