ACTINOPODOÜS HOLOTHÜRIOIDEA. 



223 



surface, and is surrounded by five minute teeth. Ambulacral 

 appendages are scattered aU over the body. On the ventral sur- 

 face, the three ambulacra are distinctly marked by longitudinal 

 rows of minute holes within which the pedicels have retracted. 

 They are most marked in the middle of the body, for in tliis 

 part pedicels are less numerous in the interambulacra than nearer 

 the two ends of the body. The dorsal surface, which is colored 

 brown, is thickly and uniformly crowded with the holes within 

 which ambulacral appendages have retracted. I have not been 

 able to ascertain whether these are pedicels or papillœ. The 



ventral surface is of 

 a lighter color. In the 

 two specimens ex- 

 amined for the pur- 

 pose, the tentacles 

 were twelve in num- 

 ber, of wliich the two 

 ventral were smaller 

 than the rest. In the 

 calcareous ring the lateral ventral radialia of both sides are re- 

 presented each by two pieces. I can not see that the ventral 

 pieces are any narrower than the rest. PoUan vesicle one, on the 

 left lateral radius. Stone-canal one, with a large lobulate madre- 

 poric body on the mesenterium. 



The calcareous deposits in the perisome are of three kinds : 

 (i) delicate, reticulate, flat cups with some knobs (textfig. -iOb), (ii) 

 thick, robust buttons with large rounded knobs (a), and (iii) plates 

 which are not very large (c). In the pedicels are found well-de- 

 veloped end-plates with longish irregular, many-holed supporting 

 rods. 



Textfig. 40. 



Colochirus imrnatus : a-Ivnobl^ed buttou ; 6— Retieiuute, 

 knobbed cup; c— rerfomted i^late. (x 300). 



