CTENOPHORES OF THE ATLANTIC COAST OF NORTH AMERICA 



23 



In the adult the body is oval, bluntly pointed above, and there is 

 considerable lateral compression, the tentacular diameter being only a 

 little more than one-half as wide as the transverse. The creature is 

 about 80 mm. long. The aboral apex is quite blunt and the oral lobes 

 are wide and about three-quarters as long as the remaining portion of 



Table showing the dimensions in mm. of specimens of B. vitrea from Tortugas, Florida, 



taken in June, 19 10. 



Speci- 

 men A. 



Speci- 

 men B. 



Total length of body 



Length from aboral apex to mouth . . . 

 Maximum width in average expansion 



of the stomodaeal axis 



Width of body in tentacular axis . . . . 



Width across expanded lobes 



Length of auricles 



Depth of cleft of sense-organ 



Length of short rows of combs 



Length of long rows of combs 



Length of funnel-tube 



80 

 58 



46 

 23 

 38 

 20 



9 

 3 7 

 73 



3 



60 

 49 



39 

 22 



45 



19 



9 



28 



57 



3 



the body. The apical sense-organ is situated in the bottom of a wide 

 but not very deep cleft (text-fig. 6) . The 4 auricles are edged by a linear 

 row of ciliary combs, and arise from the sides of the body at a short 

 distance above the mouth and close to the sides of the lappets. The 

 lappets are fiat and lanceolate and are each about one-fifth as long as 

 the entire animal. The 4 subventral rows of ciliated combs are about 

 twice as long as the 4 subtentacular rows. The combs of cilia are small 

 and numerous, there being about 80 to 100 on each subventral row and 

 40 to 60 on each subtentacular row. There is a row of short, simple 

 tentacles on each side of the mouth, extending upward along the sides 

 of the lappets to the bases of the auricles. The tentacle at the center of 

 each row on the mid-axial line is longer than the others and is provided 

 with simple, lateral filaments. The edges of the auricles are fringed 

 with long, closely-crowded cilia. The stomodaeum is long and narrow, 

 and the funnel is short, being about one-fifth as long as the stomodaeum. 

 The chymiferous tubes are of fine caliber, and the windings of the merid- 

 ional ventral tubes in the oral lappets are very simple, not complex as in 

 B. injundibulum. The oral lappets are provided with a delicate network 

 of longitudinal and transverse muscle fibers. The gelatinous substance is 

 of very delicate consistency and is either transparent or diffusely tinged 

 by a faint pink. The peripheral chymiferous tubes are of a more decided 

 pink and in the lappets these tubes often display masses of intense pink 

 color, probably due to products of digestion or excretion. 



When about 7 mm. long (fig. 16, plate 5), the body is oval with the 

 two poles of about equal bluntness. Two long, flexible tentacles arise 

 from the middle points of the sides of the body. These tentacles are 

 highly contractile and give rise to numerous short, lateral filaments. 

 They arise from the surface of the body and are not protected by sheaths. 

 The apical sense-organ consists of a capsule containing a small mass 

 of hyaline concretions. It lies at the bottom of a shallow depression. 

 There is as yet no trace of the lappets, but the adjacent meridional sub- 

 ventral tubes have fused, forming simple, closed loops. The 4 meridi- 

 onal subtentacular tubes have joined with the circumoral vessel. When 



