95 



and its radial tubes has thickened and invaginated to form the nerve 

 ring and its five radial branches. 



Fig. 1. 



Fig. 1 — 5. CM, Cellular mass; E.E, Epigastric Enterocoel; E.T, End Tentacle; 

 IT, Hydrocoel; H.E, Hypogastric Enterocoel; M, Mouth; Oe, Oesophagus; P, Pore 

 canal; .S, Stomach; T^, First pair Foot Tentacle; T-, Second pair Foot Tentacle ; 

 Wr, Water ring. 



Protruding from the furrows caused by the sinking in of the ner- 

 vous system, are to be seen the five tentacles now present in each 

 radius. 



