CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 33 



for when the ciliated epithelium is stretched through the contraction of 

 the underlying muscles the cilia are stopped, but if the muscles be re- 

 laxed, as by magnesium, the surface tension is reduced and the cilia 

 are free to beat. 



Fig. io. — Mnemiopsis mccradyi, from life by the author. Natural size. Let- 

 tering as in fig. 9. Port Royal, Jamaica, May i, 191 1. 



Mnemiopsis gardeni L. Agassiz. (Fig. 47, plate 8.) 



Mnemiopsis gardeni, Agassiz, L., i860, Cont. Nat. Hist. U. S., vol. 3, pp. 269, 290, 

 figs. 95, 96. — Agassiz, A., 1865, North Amer. Acal., p. 20, figs. 20, 21. — Chun, 

 C, 1898, Ctenophoren der Plankton-Exped., p. 25. 



(?) Bolina littoralis, McCrady, 1859, Proc. Elliott Soc, Charleston, vol. i, p. 254, 

 plate 14, figs. 1-14 (development). 



This is a small species, being only 35 to 40 mm. long when mature. 

 The oral lobes are of very small size, being only one-fifth to one-sixth as 

 long as the body of the animal. The auricles, however, are well developed, 

 being relatively about as long as in M. leidyi and about one-third as long 

 as the entire body of the animal. There is considerable lateral compres- 

 sion, the sagittal diameter being about 2.5 times as great as the tentacular. 

 The 4 deep lateral furrows extend from the level of the mouth about 

 three-quarters the distance up the sides of the body. They are not as 



