4 Reproductive System of the Corynidae and Sertulariadse. 



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 sporosac 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 sporosac minus the ectotheca and mesotheca. 



The gonophore is borne as a bud, on the one hand directly 

 either by the ccenosarc (Cordylophora, Eudendrium) i 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 Tubularia 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 Sertulariadse 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. 



