BIGELOW: THE CTENOPHORES. 393 



that we can safely say that the closest relationship of hydatina is with 

 vitrea, not with infundibulum as Mayer ( : 12) supposes. 



Bolinopsis mikado, likewise, has short auricles and simple lappet- 

 canals so far as the latter could be traced, but the sense-body is much 

 more deeply sunken than in any other Bolinopsis ; and the structure 

 of the ribs further differentiates it. It is highly desirable that better 

 material of this interesting species be studied. The same is true also 

 of elegans, which is characterized, according to Mertens, by the pres- 

 ence of numerous papillae on the outer surface of the body, lacking 

 in other species of Bolinopsis. 



Bolinopsis chuni has been described in detail by Lendenfeld: its dis- 

 tinguishing features, as noted by Moser ( : 08a, p. 56), are the extraor- 

 dinary thickness of the lappets, the simplicity of the lappet-canals, 

 and by the fact that the gastric canals lie at some distance from the 

 stomach. 



Bolinopsis vitrea (L. Agassiz). Mayer. 



Bolina vitrea L. Agassiz, '60, p. 269, 289, fig. 93; A. Agassiz, '65, 

 p. 19, fig. 19; Mayer, :00, p. 81, pi. 27, figs. 91, 92; Moser, :08a, 

 p. 53. 



Bolinopsis vitrea Mayer, :12., p. 22, pi. 5, fig. 16-19. 



Acapulco Harbor, 4 specimens, 10-82 mm. long. 



Unfortunately I was unable to preserve any specimens. Although 

 I tried various preservatives and various methods of stupefaction, 

 all the bottles were found after the journey across the continent 

 to contain nothing but a gelatinous mass of fragments. But as I 

 foresaw from my experiences with B. infundibulum that this might 

 happen, detailed drawings and notes were made from life, and the fol- 

 lowing account is based upon these. 



1. Adult. Two large specimens, 82 and 69 mm. long, were taken 

 and kept under observation for several hours. The largest, when at 

 rest (Fig. A), lay with the lappets touching. In this position its long- 

 est diameter at the level of the top^of the auricles was slightly half 

 its length; and the lappets extended beyond the mouth for a distance 

 equal to about | of the length of mouth-pole. That is to say, the 

 stomach was comparatively long. The auricles are short: they arise 

 at the mid-level of the stomach, and do not quite reach the mouth, 

 thus bearing the same relation to the gastric system that. they do in 



