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 fringes of the adult. In Fig. 



Fig. 34. 



Fig. 35. 



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. 36. 



Fig. 37. 



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 hatching 5 magnified. 



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

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



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



