HYDROMEDUSAE, SIPHONOPHORES, AND CTENOPHORES. 303 



ish gonads in pyramidalis, reddish in gibbosa, is one which has 

 often been found to occur among Eucopidae, as in Phialucium 

 mbengha. The evidence as yet available shows no valid distinction 

 between the two, but to determine this point requires a fresh study 

 of specimens from Charleston, South Carolina, the type-locality of 

 gibbosa. I may point out here that Mayer's statement that in 

 pyramidalis tentacles and otocysts alternate regularly is not alto- 

 gether correct, for in every example which I have seen there are some 

 young tentacles in process of development, and a certain amount of 

 irregularity in the arrangement of otocysts. Thus I have seen three 

 between two tentacles, and, on the other hand, two tentacles without 

 any intervening otocyst. On the whole, moreover, the number of 

 otocysts is always greater than that of mature tentacles, at least in 

 large specimens. Excretory pores are present and easily distin- 

 guished. 



Phortis lactea may be a young pyramidalis in which the gonads 

 have appeared a little sooner than usual. A comparison of the fig- 

 ures of the two by Mayer (1910) will show how closely they agree. 

 But not having seen any specimen of the lactea type I am not pre- 

 pared to make definite location of it. 



P. pellucida and the gibbosa-pyramidalis group agree in the thick 

 bell and broad, comparatively short, peduncle. I have not seen any 

 specimens of pellucida myself. 



P. palkensis, ceylonsis, kambara and elliceana all agree with each 

 other, and differ from the preceding, in having a long narrow pe- 

 duncle. P. kambara was based on a single specimen, 8 mm. in diam- 

 eter, so young that no trace of gonads is yet to be seen (Agassiz 

 and Mayer, 1899, pi. 8, fig. 29). The absence of tentacular knobs 

 suggests that it may be a stage in the development of ceylonensis. 



Palkensis and ceylonensis, the latter recently recorded by Van- 

 hoffen (1911-1912), are separated b} 7 the marginal organs; the for- 

 mer having few (48 or less) tentacles and a large number of per- 

 manently rudimentary bulbs, the latter a large number of tentacles 

 and few or no rudimentary bulbs. There is also a difference in the 

 structure of the otocysts (Browne 1905). Ceylonesis is represented 

 in the present collection. 



Elliceana was described by Agassiz and Mayer (1902) from a sin- 

 gle immature specimen, 16 mm. in diameter; it has not been re- 

 corded since. There are several specimens in the present collection 

 which apparently belong to it, and which are easily distinguished 

 by the structural characters noted below (p. 305), from all other 

 members of the genus. 



