4 Reproductive System of the Corynide and Sertulariade. 
The endotheca and spadix, taken together, form the manu- 
brium. The endotheca is the ectoderm, and the spadix the 
endoderm of the manubrium. It is between the endotheca and 
spadix that the generative elements are developed. 
Professor Huxley would restrict the term manubrium to “ the 
central polype-like sac of a medusiform gonophore, which is 
surely the homologue of the whole sporosae of Hydractinia, and 
not of its central cavity only.” I admit that, in some of my 
earlier papers, I was not very clear myself on the homologies in 
question ; and Professor Huxley, manifestly misled thereby, has 
here stated my views as somewhat different from what they 
really are. For me, however, as I at present understand the 
matter (see Rep. Brit. Ass. for 1858, Trans. Sec. p. 120, and 
Proc. Roy. Soc. Edinb. Dec. 1858), the manubrium is the whole 
of the “peduncle,” “stomach,” or by whatever other name it 
may be called, which depends from the centre of the umbrella 
in a medusa or medusoid; and I apply the same term to what 
I consider the homologous part in a sporosac,—namely, the 
whole sporosace minus the ectotheca and mesotheca. 
The gonophore is borne as a bud, on the one hand directly 
either by the coenosarc (Cordylophora, Eudendrium), or by the 
polype (Coryne); or, on the other hand, by a special column- 
like support, from which it is also developed as a bud (Laomedea, 
Sertularia, Tubularia). This support is the blastostyle. 
The blastostyle with its gonophores may be naked (Tubularia, 
Hydractinia), or it may detach from its sides a layer of ecto- 
derm, which will secrete upon its external surface a chitinous 
polypary in the form of a capsule or gonangium, whose axis 
will then be occupied by the blastostyle in the form of a column 
carrying the gonophores on its sides. 
Prof. Huxley would restrict: the term blastostyle to the axis 
of the capsule in such forms as that last described, and believes 
that when the stalk of the gonophores in Jubularia is also 
called so, the same name is applied to two different things,— 
this part in Tubularia containing the representatives of both the 
blastostyle and capsule of Laomedea. 
In one sense this is true—in that, namely, in which it is true 
that the naked polype of Tubularia contains the representative 
of both the hydrotheca* and polype of Laomedea; for there can 
* The term hydrotheca has been proposed by Huxley to designate the 
cup-shaped receptacle in which the polypes of the Sertulariade are lodged, 
and which is commonly known as the “polype-cell.” It is a valuable 
addition to our terminology of these animals, and is particularly useful in 
enabling us to avoid the ambiguity which attaches to the word “ cell” 
when used in this sense, now that we have in histology an entirely different 
application of the term. 
