REPORT ON THE HOLOTJIURIOIDEA. 25 



resembling those I have represented in Orphnurgus asper. The pedicels are ten all 

 along each side of the ventral surface, the posterior pairs being somewhat smaller than 

 the others, which are of rather a remarkable size. The first five or six pedicels on 

 either side are distinctly separated from one another by certain distances, while the other 

 ones are close-set side by side ; the former are directed downwards and slightly back- 

 wards, while the latter or posterior ones are directed outwards and backwards, pro- 

 ceeding from the margin of the very thin posterior end of the body. The wide canals 

 of these posterior pedicels are continued directly inwards and traverse without dis- 

 cernible diminution the brim-like thickened perisoma, which surrounds the hind-part of 

 the body ; hence one cannot help thinking that these pedicels are also in reality long, 

 but have their ends alone free, being for the rest of their length webbed together by an 

 extension of the integument. From these close lying canals being visible through the 

 skin, the posterior extremity of the body has almost a fin-like appearance. In addition 

 to the three above-mentioned lobe-like appendages, there are on the dorsal surface some 

 minute processes, one placed on the right ambulacrum and two on the left. The 

 integument is whitish, rather thin and transparent. The larger calcareous deposits 

 (PI. XXXIII. fig. 10) have their four arms about 0"2 mm. long, almost straight or 

 slightly curved with a number of large spines, each arm sending out one or several 

 spinose processes ; they have no central processes, lie in the internal layer of the con- 

 nective tissue of the body-wall, and are to be found in greatest number on the sides 

 of the body. The other calcareous deposits are far more numerous. Their four 

 arms are only half as long but more curved and covered with considerably smaller 

 spines ; the arms either meet in a central point or are united by a shorter or longer 

 rod-like central part. These deposits have either a single slightly spinose, straight 

 process proceeding from the centre, or two to four similar ones, situated more or less 

 distant from the centre ; those with two to four processes predominate on the ventral 

 surface, while those with only one process are to be found on the back and in the 

 pedicels, where the process attains a considerable length. 



I have occasionally seen some C-shaped bodies, but their rarity has made me fear 

 that they do not belong to the animal, but have happened to stick to the skin. 



The oral disk contains, besides the four-armed deposits with four processes, un- 

 branched spicula as well as three-, four-, and many-armed, irregular, finely spinose bodies. 

 The ends of the tentacles and pedicels are provided with numerous larger or smaller, 

 straight or slightly curved, spinose spicula (PL XXXIII. figs. 11, 12); besides, the ends 

 of the pedicels contain some four-armed slightly spinose deposits. 



Each of the five separated pieces of the calcareous ring (PI. XXXVII. fig. l) is com- 

 posed of a small oblong central part, each end of which sends out a radiating bundle of ten 

 to fifteen rods, which have their extremities more or less ramified and flattened. These 

 five pieces constitute the radial parts of the ring, while every trace of inter-radial pieces 



(ZOOL. CHALL. EXP. — PART. XIII. — 1881.) N 4 



