574 



EC HI N ODER MAT A HOLOTHUROIDEA 



marked sole, to which the tube-feet are confined, whilst the 

 dorsal radial canals, and consequently all the dorsal tube-feet, are 

 absent. The dorsal ossicles are enlarged to form a complete mail 





ml 



wmwwti 



Fig. 260. Phyllophorus urna. x 1. 



B 



Fig. 261. Psolus ephippifer. x 3. A, with feelers retracted and brood-pouch closed ; 

 B, with feelers extended and some of the plates of the brood -pouch removed. 

 (From Wyville Thomson.) 



of plates, recalling the corona of a Sea-urchin. The two British 

 species are small, and found in comparatively deep water, but 

 a fine large species is found in the Gulf of St. Lawrence, and 



