172 Prof. Allinan on the Hydruid Zoophytes. 



C. capillare, Alder. 



Zoophyte erect, rising to half or three-quarters of an inch in 

 height from a creeping radicular tube ; much and irregularly 

 branched; branches of equal thickness with the main stems, 

 capillary, ringed at their origin ; branches which carry the 

 gonophores short, lateral or else springing from the creeping 

 basal tube. Polypes with about 24 or 26 tentacula. Gono- 

 phores pure white. Polypes light brown, becoming darker 

 and more opake in the older parts. 



The general character of the polypes, ccenosarc, and polypary 

 of the present zoophyte is that of the genus Eudendrium. The 

 remarkable umbelliforra clusters, however, in which the gono- 

 phores are borne on the summits of non-poly piferous branches, 

 afford a character whose importance cannot be neglected, and 

 which renders it necessary to separate from that genus the 

 subject of the present communication. 



The whole zoophyte is very minute, and may in consequence be 

 easily overlooked. The only specimens I obtained were attached 

 to a piece of Delesseria sanguinea brought up in the dredge from 

 a depth of about four fathoms. They adhered to the fronds of the 

 Alga by a creeping, branched and anastomosing radicular tube. 



The male gonophores (no specimens of the female having yet 

 been seen by me) are supported each on a short peduncle. 



The umbel-like clusters in which they are grouped have been 

 fully noticed by Mr. Alder; they contain usually from ten to 

 fifteen gonophores in each cluster. The ramuli on whose ex- 

 tremities they are borne are shorter than the fully-developed 

 polypiferous ramuli, and arise further back than these, springing 

 either from the principal branches or directly from the radicular 

 tube. 



The ramuli which thus carry the gonophores contain an exten- 

 sion of the ccenosarc, which becomes naked at their extremities 

 and there enlarges into a common basis for the support of the 

 cluster. This enlarged basis, though entirely destitute of mouth 

 and tentacles, is manifestly the representative of a polype, and 

 corresponds to the gonoblastidia of Dicoryne. 



The structure of the gonophore is remarkable. Its peculiar 

 moniliform shape has been noticed by Mr. Alder. At first this 

 body is in the form of a spherical sac raised on a short peduncle. 

 It contains a large simple spadix, which occupies the entire 

 axis of the sac, and which soon becomes surrounded by the 

 spermatogenous tissue. A small cellular mass next shows itself 

 on the summit of the gonophore, and increases in size, while its 

 interior becomes hollowed out into a cavity which communicates 

 with that of the gonophore. Into this cavity the spadix gradually 



