PHIALIUM. 153 



abandoned, for the peduncle is a feature which is variable, and may even 

 be present to a slight degree in adults of such genera as Phialidium and 

 Phialucium, so that among the species with numerous otocysts there is no 

 break in the series from forms without peduncle to others in which this organ 

 is well developed. The interrelationships of these genera are so puzzling 

 that no altogether satisfactory subdivision of them has yet been devised. 



Maas (: 05) has recently transferred the subfamily Octocanninae, with 

 eight radial canals, from the Aequoridae to the Eucopidae, and on suffi- 

 ciently good grounds. 



Phialium Haeckel, 1879. 



Eucopidae, with twelve otocysts, and four chief radial tentacles flanked at 

 their swollen bases by lateral cirri ; with or without additional tentacular 

 bulbs on the margin ; without peduncle. 



This genus was instituted by Haeckel ('79) to contain the Eucheilota 

 duodecimalis of A. Agassiz ('65), which, as A. Agassiz had pointed out, differs 

 from the Eucheilota veniricularis of McCrady ('57) in having twelve instead of 

 eight otocysts, and which A. Agassiz thought would be found, when better 

 known, to belong to another genus. Haeckel added a second species, P. dode- 

 cascma, from one of Agassiz's figures, believing that the latter had observed 

 two distinct species; but Fewkes (*82 b ) has shown that the two supposed 

 forms represent merely two contraction phases of the one species. The 

 genus has been accepted by Fewkes f82 b ), but so far as I can learn it 

 has not appeared elsewhere in literature, both Mayer (: 00 b ) and Hargitt 

 (: 05 b ) having used the name Eucheilota in a broad sense to include both 

 species with eight and those with twelve otocysts. It is best to retain 

 Haeckel's genus, as distinguished from Eucheilota, inasmuch as it is 

 separated from the numerous species with eight otocysts (Eucheilota), not 

 only by the number of these organs, but also by the limited number of de- 

 veloped tentacles (four radial) and by the extreme development of the 

 gonads. 



I have been able to find no other species which can certainly be referred 

 to this genus, although it is possible that Mitrocomium assimile Browne (: 05 b ), 

 from Ceylon, may belong here. The present collection contains a consider- 

 able series of specimens indistinguishable from Phialium duodecimalis from the 

 Atlantic coast of the United States. 



