THE HOLOTHURIDEA. 



471 



Fig. ISQ.—Synapfa diqitnta and inJicercm (After Banr.") i 



A, larva with the bilnteral ciliated band, and wheel-shapod calcareous plates: 

 ventral view, a, moulh and ffullet : ft, stomacli ; c, intestine and anus; rf, sacs 

 of the enterotoele (sausasre-shaned bodies) at the sides of the stomacli ; e, riuii- 

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

 larva in which the oral aperture is obsolete (the so-called " pupa-sta-e ). ?"0 .^"6 

 cilia are arrancrpd in zones, i, tentacnla; k. Polian vesicle ; /. the longitiimi.ai 

 muscles of the bodv-wall. C. a vonne Synapta. in whirh the 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 cavity ol tue 

 bodv. B. a youm; Siprnptn inhcerens with anchor-shaped calcareous spiciila ex- 

 cept at the hinder end of the body, where they are small and polygonal. J^, ion- 



1 ''Beitnige zur Naturgeschiclite dcr Synapta digltatay ("Nova Acta," 

 xxxi., 1864.) 



