I^HE HOLOTHURIDEA. 



471 



FxG.ISQ.—Siynapta dif/ifafafim} inlicerens (After Banr.) ^ 



A, larva with the bilateral ciliated hand, and wheel-shaped calcareous plates: 

 ventral view, a, mouth and jrullet ; b. stomach; c, inte^^tine and anus; d, saca 

 of the enterocoele (sausafre-shaoed bodies) at the sides of the stomach ; e, rudi- 

 ment of the ambnlacral vascular system. B, further advanced condition ot the 

 larva in which the oral aperture is obsolete (the so-called " pupa-staae'"). and the 

 cilia are arranged in zones, i, tentacnla: k. Polian vesicle ; /. the longitudinal 

 muscles of the bodv-wall. C. a voun;; Si/napta. in which tlie ciliated zones have 

 disappeared ; with" its five tentacles and the wheel-shaped calcareous bodies at 

 its hinder end m. the madrenoric canal which now opens into the cavitv of the 

 bodv. B. a voun':^ Synapfa inhcerens w\ih anchor-shaped calcareous spicula, ex- 

 cept at the hinder end of the body, where they are small and polygonal. E, lon- 



» ''Beitriige zur Naturgeschichte der Synapta digitata.'''' ("Nova Acta," 

 xxxi., 1864.) 



