CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 27 



The adult animal (figs. 42, 43, 46, plates 7 and 8) is about 100 mm. 

 in^length, specimens larger than this being rare. When seen from the 

 narrow side, the general outline of the body is almost ellipsoidal. A view 

 of the broad side, however, shows a pear-shaped outline, this being due 

 to the wide-flaring oral lappets. The aboral apex is not so acute as in 

 Bolinopsis injundibulum, and not so blimt as in Lesueuria hyboptera. The 



Fig. 8. — Sense-organ of Mnemiopsis leidyi. From life, by the author, 

 at Newport, Rhode Island, ad, adradial canals; c, cilia at aboral 

 end of stomodaeum ; /, funnel or entodermal center of gastro- 

 vascular sjstem; ft, axial-funnel canal; g, paragastric canal; 

 t, interradial canal; mu, connective tissue strands; p, pole plate; 

 st, stomodaeum; t, tentacular canal. 



apical sense-organ (text-fig. 8) contains a mass of highly refractive con- 

 cretions, and lies at the bottom of a moderately deep cleft. The oral 

 lappets are each about two-fifths as long as the entire animal and are 

 even wider than they are long. The 4 auricles are flat and ribbon-like, 

 and about one-fourth as long as the body of the animal. Their centrif- 



