138 PROCEEDINGS OF UMTED STATES NATIONAL MUSEUM. [IriS."). 



bent. If extended some of these villi would more than reach across the 

 lumen of the intestine. This is their condition in the foetuses of several 

 species of Embiotocoids examined by me ranging from 1 to l^ inches 

 in total length. 



As development proceeds the gut begins to assume its normal dimen- 

 sions posteriorly. It becomes narrower, and the sigmoid turn or flexures 

 of the intestine more pronounced. The villi also diminish in length, 

 and become far less numerous in foetuses If inches long. At this stage, 

 also, the projection of the rectum below the abdominal profile becomes 

 less marked, and in fact is scarcely apparent. 



^In the adults the posterior part of the intestinal canal exhibits no 

 such dilatation and dense internal garniture of villi as is seen in the 

 foetus ; iu fact,*the hind-gut of the fully-grown fishes presents nothing 

 unusual when compared with that of the usual type. 



It is therefore obvious that this hypertroj)hy of the hind-gut and re- 

 markable development of elongated villi in the embryos of the surf- 

 perches has some important function to subserve during foetal life. As 

 suggested at another place, that function seems to be digestive; and 

 as it is not at all improbable that the fluids secreted by the walls of the 

 ovarian sac are nutritive; it seems likely that the foetal fishes swallow 

 such nutriment while still in the ovary. If Dr. Blake is correct iu stat- 

 ing that the ovarian duct is occluded by a mucous or membranous 

 plug during gestation, this interpretation of the function of the gut of 

 the embryo would seem all the more likely to be the correct one. 



IV. — The intra-ovaeian respiratory function of the verti- 

 cal FINS OF EmBIOTOCOID FISH EMBRYOS. 



Two papers on the intra-ovarian gestation of the embryos of the Em- 

 biotocidre, Holconoti, or surf-perches of the Pacific coast have been pub- 

 lished by Dr. James Blake,* in the first of which the singular vascular 

 lobes extending beyond the rays of the vertical fins, as productions of 

 the inter-radial membranes, are for the first time described and figured. 



I reproduce the following from Dr. Blake's second paper, as it will 

 serve to indicate the extent of his contributions to the subject under 

 consideration : v 



" The manner in which the young of the Embiotocoid fishes is nour- 

 ished until it escapes from the ovary has not, that I am aware, been 

 satisfactorily explained. In this class of fishes the young remain in the 

 ovary until they are apparently as perfect as the adult fish. As during 

 the process of gestation the ovary is cut off" from all communication 

 with the water, the external orifice being sealed up by a dense layer of 

 epidermis or inspissated mucus, it is evident that the foetal fish must 



* 1. On the nourishment of the foetus in the Embiotocoid fishes. Proc. Calif. Acad, 

 of Nat. Sci., iii, 1867, pp. 314-317, 3 figs, in text. 



2. On the nourishment of the foetus in Embiotocoid fishes. Journ. Anat. and Phys- 

 iol, ii, 1868, pp. 280-282, 



