XII 



PHYLUM MOLLUSCA 



777 



mesenteron. From whatever source it may be derived, the latter 

 becomes distinguishable as a cell-plate which becomes converted 



ftr.i 



yk.s 



.s 



Fio. 710. Two later stages in the development of Loligo. A, from the funnel side; B, 

 obliquely from above. Letters as in preceding figures ; ne. cart, miehal cartilage. (After 

 Korschelt and Heider.) 



B 



yk.s 



J''IG. 711. Two stages in the development of Loligo, later than those rr|,iv-riiti-d in Kig. 7 In. 

 From the anal or funnel side. Letters as in preceding ligun- ; in addition, fin, fins ; fun. 

 funnel. (After Korschelt and Heider.) 



into a vesicle at first opening below against the yolk epithelium, 

 there never being any direct communication with the yolk. An 



