50 Prof. Allman on the Hydroid Zoophytes, 



tremity to the endoderm of the manubrium, and thence radiating 

 in all directions, fill the interspace between the endoderm and 

 ectoderm with a dense tissue, in whose component tubules the 

 spermatozoa, with their generating cells, are formed. 



II. Podocoryne caimea. 



I recently obtained, upon stones in rock-pools near low-water 

 mark, and on old shells brought up upon the lines of the fisher- 

 men, a zoophyte w^hich appears to be identical with a species 

 described by Sars under the name of Podocoryna albida, — an 

 animal, however, which seems to be only a variety of the zoo- 

 phyte described by the same author under the name of P. carnea. 



It consists of a colony of colourless claviform polypes spring- 

 ing from a common tubular basis, which invests the surface of 

 the stone or shell. The polypes are of two kinds, of which one 

 rises to the height of about \ inch above the common basis. Its 

 extremity is club-shaped, and bears a terminal mouth, behind 

 which is situated a series of about twelve filiform tentacula, 

 arranged in a single verticil. The polypes of this kind never 

 bear gonophores ("generative vesicles ^^). 



The other kind of polypes spring, in common with those just 

 described, from the tubular base. They are scarcely half the 

 size of the former, and have only four or five tentacula, which 

 are situated, as in the larger polypes, behind a terminal mouth, 

 while, at a short distance behind the tentacula, there is always 

 borne a verticil of medusiferous gonophores, generally four or 

 five in number, each supported on a short peduncle. 



Sars, in his description of P. carneaj states that the polypes 

 are connected to one another by *^ a kind of foot or mantle, 

 which forms upon the shells a thin membranous investment, 

 and which appears to consist of numerous stolons anastomosing 

 with one another -/' but he makes no mention in this descrip- 

 tion of a chitinous polypary. 



He tells us, however, a little further on, that, "after the 

 death of the polype, the mantle remains behind as a brown 

 epidermal investment, bearing numerous pointed spines of a 

 homy nature, and which we may probably consider as a kind 

 of polypary/' He has met with this investment upon shells 

 from different seas. 



This latter part of his description is not consistent with the 

 former ; and it seems probable that he has confounded the solid 

 muricated and chitinous basis of Hydractinia with the tubular 

 basis of the present genus. 



Sars describes his zoophyte as naked ; but I believe this is 

 not admissible as a character in any of the known marine Hydroid 

 zoophytes, unless it be in Hydractinia, in which the solid chi- 



