434 EMBRYOLOGY OF THE LOWER VERTEBRATES ch. 



Flo. 200. — Stages in the development of Lepidosiren 

 paradoxa. 



A, stage 23 ; B, 25 ; C, 26 ; D, 28 ; E, 31 ; F, 33 ; G, 35 ; 

 H, 36. c.o, cement organ ; E, eye ; e.g, external gill ; M, 

 mouth ; p.f, pectoral iin ; plf, pelvic fin ; sp.v, spiral valve of 

 intestine. (A-Fx3 ; Gx 2-5 ; 11x2.) 



