DEVELOPMENT OP THE STAEFISH SOLASTER ENDECA. 71 



PLATE V. (cont). 



space on the side turned towards the axial sinus, into which it freely opens. 

 For diagrammatic purposes one or two of the structures are shown as 

 slightly more advanced in development {e. g., radial cseca of stomach, r.d.) 

 and others less advanced (e.^., pharyngeal ccelom) than they should be 

 at this stage. ( x 60.) 



Fig. 54. Diagram of internal cavities in a stage similar to that of fig. 50, but viewed 

 from right side of larva. From this side the hydropore (m.), the dorsal 

 sac (d.s.), and the right lateral diverticulum of the anterior ccelom (r.l.c.) 

 are seen. 



Fig. 55. Diagram from aboral (right larval) side of specimen a little younger than that 

 from which fig. 52 was taken. The epigastric ccelom (right lateral diverti- 

 culum of anterior ccelom) (r.l.c, ep.c.) is being separated from the axial 

 ccelom. For diagrammatic purposes the preoral lobe is represented as 

 standing out much straighter than it should be at this stage. It should 

 now be bent so far to the left as to be almost entirely concealed by 

 the disc. 



Fig. 56. Diagram from aboral side of specimen well advanced in metamorphosis. The 

 epigastric ccelom is completely separated from the axial ccelom. As in 

 fig. 55, the remains of the preoral lobe are straightened out for diagrammatic 

 purposes. 



