54 
present exceedingly delicate tubules, filled with the spermatogenous 
cells seems evident, and then they will be the exact equivalent of the 
pyriform ovigerous tubes of the female. It is quite possible, that in 
both the male and female sacs, the tubes containing the spermatozoa 
in the one, and the ova the other, open into the cavity of the manu- 
brium ; and thus facility would be at once afforded for the sperma- 
tozoa to gain access to the ova. I have never, however, succeeded 
in demonstrating such a communication. 
Indications of the ova and spermatogenous cells being confined at 
an early period within delicate membraneous tubes may be witnessed 
in other species, but in no case have I succeeded in demonstrating 
such a condition so plainly as in the present species. 
The spermatozoa have the usual form of caudate corpuscles. The 
zoophyte dioecious. 
Clava multicornis. 
In this species, the gonophores are borne upon the clavate body 
of the polype, just where it passes into the stem, and immediately 
behind the posterior tentacula. They are compound, each consisting 
of a cluster of sporosacs attached to a short blastostyle, but are des- 
titute of investing capsule. I have observed in the same colony two 
kinds of polypes, — the ordinary tentaculiferous polypes, and others 
destitute of tentacula, and consisting merely of a columnar stem, 
scarcely clavate at its extremity, and destitute of mouth. The 
gonophores were borne on both kinds of polypes. The male and 
female gonophores are separate on distinct colonies. 
The manubrium of the sporosac is simple ; and there are no radi- 
ating canals. In each sporosac (female) there is usually a single 
ovum, though I have occasionally witnessed two. The germinal 
vesicle is visible in the ovum, and the process of segmentation may 
be distinctly traced. 
As development proceeds the ovum becomes elongated, and it may 
be seen to be invested by a proper membrane, apparently structure- 
less. Within this membrane a distinct dermal layer now begins to bo 
differentiated from the ovum ; while at the same time a cavity is 
formed within it, and the embryo may now frequently be seen doubled 
upon itself. At this stage it is ready to escape from the sporosac, 
which gives way for its exit, and the embryo may then be seen swim- 
ming through the surrounding water by the aid of the minute vibratile 
