58 THE MEDUSAE. 



the breadth of the gastric pouches, and in the number (three) of otocysts on 

 each lappet, a character which appears to be constant, at least for the pres- 

 ent specimens. The bell is rather high, and somewhat conical; the gelat- 

 inous substance thick. In life the bell is seldom circular, but usually more 

 or less triangular, the result of the weakness of the mesogloea and the vigor- 

 ous contractions of the subumbrellar muscles, a condition common in C. kdi- 

 ventris (Maas, : 04°, p. 31). The exumbrellar surface is smooth, without 

 ridges or other sculpture. In one specimen there are fourteen, in each of 

 the others thirteen tentacles about as long as one third the diameter of the 

 bell, and frequently recurved into the cavity of the latter. In consequence 

 of the shortness of the marginal lappets the tentacles arise but a short distance 

 from the margin. There are no nematocyst pads at the bases of the tentacles 

 such as occur in C. peregrina, the other member of the genus taken during 

 the expedition. It is probable that the presence or absence of these pads 

 will prove, when more fully known, to be an important specific character. 

 Another constant difference between the two species is in the structure of 

 the tentacles. In C. globosa the endoderm cells forming the core of the 

 tentacle preserve the chordate form out to the tip of the tentacle, and near 

 the tip, which is slightly swollen, the ectoderm is crowded with nematocysts 

 (PI. 17, fig. 3). In C. peregrina, on the other hand, the endoderm cells 

 become nearly cubical near the tip, and there is no such nematocyst swell- 

 ing. This difference does not seem to be due to different decrees of con- 

 traction, since it was to be seen in all the tentacles of the two species which 

 I examined. It may perhaps be correlated with the difference in the flex- 

 ibility of the tentacles in the two species, these organs being much more 

 mobile in C. globosa than in C. peregrina. The marginal lappets are very short, 

 and but slightly rounded in outline. The peroniae are correspondingly 

 short and covered over by the union of the gelatinous substance of the 

 two adjacenl lappets. 



Tin- number of otocysts, three per lappet, is unusually small for the genus. 

 This number is constant in all the lappets of these four specimens, and since 

 all arc sexually mature, there is no reason to suppose that the number of these 

 organs would increase further. The otocysts themselves (PL 17, fig. S) are of 

 tic usual Cunina type, so well known through the studies of the Hertwigs 

 in (,'. Jatii'fiilrix, Each contains two or three large otoliths. It is 

 probable that in life the otoliths were more prismatic than I have rep- 

 uted them < 1*1. 17, liir. 8), since they were not examined until after 



