192 SYNOPTIC COLLECTION. 



Pedata. One of the more generalized members of the 

 Pedata is Holothiiria tubulosa Tied. (No. 361, model), 

 in which the body exhibits a distinct antero-posterior 

 axis. This genus has the feet scattered over the surface 

 instead of being arranged in rows. 



Another representative of this group is Pentacta fron- 

 dosa Jaeger (No. 362), in which the division of the body 

 into five distinct areas is finely shown. Two double rows 

 of ambulacral feet extend down the dorsal side and three 

 on the ventral side. There are also dorsal feet in the 

 interambulacral areas. The terminal mouth is surrounded 

 by numerous organs resembling tentacles but which serve 

 as branchiae or external gills. The madreporic body is 

 internal. The anus is at the posterior end, and the 

 respiratory tree is given off from the cloaca near the vent. 

 This is seen in No. 363 which is a dissection showing 

 chiefly the digestive and reproductive systems. 



A peculiar modification of structure is seen in Psolus 

 fabrici Semper (=.Lophothuria fabrici Verr.) (No. 364), 

 where the lower surface is converted into a creeping-disc 

 resembling the foot of a gastropod. It has three rows of 

 ambulacral feet and there are none on the scaly dorsal 

 side. 



Cucumaria crocea Less., in its development skips alto- 

 gether the larval stage and enters upon the adoles- 

 cent or neanic period. The young of Cucumaria crocea 

 Less. (PI. 365, fig. i, dorsal side; fig. 2, ventral side), 

 were found by Sir Wyville Thomson 1 attached to the two 

 rows of ambulacral feet on the back of the mother. 

 They were all "miniatures of their parents," excepting 

 that their dorsal ambulacral feet were in an undeveloped 

 condition, while their ventral feet were early and well 

 developed and used for clinging to the parent. The 

 adult like the larva is elongated with distinct rows of feet 



iQtioted by Th^el in Chall. Rep., Zoo!., XIV, part 32, 1886, 

 p. 60. 



