EMBRYOLOGY OF CTENOPHOR^. 35 



than that of the other Ctenophorae. Figs, 34, 35, and 36 show 

 the Pleurobrachia at various stages of growth ; Fig. 34, with its 

 thick stunted tentacles and short rows of flappers, is the youngest; 

 the flappers themselves are rather long at this age, looking more 

 like stiff hairs than like the minute fi-uiges of the adult. In Fig. 



Fig. 34. Fig. 36. 



35 the tentacles are already considerably longer and more deli- 

 cate ; in Fig. 36 the vertical tubes are already completed, while 

 Figs. 27-29 present it in its adult condition. 



The Idyia differs greatly in appearance at different periods of 



Fig. 38. Vig- 3T. 



its development, and, indeed, no one would suspect, without some 

 previous knowledge of its transformations, that the young Idyia, 



Fig. 34. Young Pleurobrachia still in the egg ; t tentacles, e eye-speck, c c rows of locomotive flap- 

 pers, d digestive cavity; greatly magnified. 



Fig. 36. Young Pleurobrachia swimming about In the egg just before batching ; magnified. 



Fig. 36. Young Pleurobrachia resembling somewhat the adult ; /funnel leading to anal opening, / 

 lateral tubes, c c c' c' rows of locomotive flappers; magnified. 



Fig. 37. Young Idyia, greatljr magnified ; lettering as in Fig. 36 ; d digestive cavity. 



