VII 



MOLL USO A ONTOGENY 



267 



FIG. 222. Various stages in the development of Sepia (after Koelliker). A, B, C, D, 

 Anterior view ; E and F, from the left side ; G and H, from behind. Lettering as in Fig. 221. In 

 addition : d, rudiment of the funnel-nuchal muscle (collaris) ; d], paired rudiment of the funnel 

 proper ; p, yolk ; ai, edge of the mantle ; t , optic invagination (?) ; , region of the shell ; q, edges 

 of the two rudiments of the funnel bent round ; r, fins. In G the mantle fold is raised up in H 

 cut off. 



