ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 979 



tion, which relate to the development of the intestine and the vascular 

 supply of the median fins. 



The paper is subdivided as follows: — I. Development of Anableps. 

 IL Development of the Embiotocidpe of the Pacific coast. III. Hyper- 

 trophied hind-gut of Embiotocoid embryos and its subsequent dimi- 

 nution in relative size. IV. Intra-ovarian respiratory function of 

 the vertical fins of Embiotocoid fish embryos. V. Development and 

 intrafollicular gestation of Gambusia patruelis, concerning which a 

 number of points that had been left undecided have been deter- 

 mined : — (1) Fertilization of the egg of Gambusia occurs within the 

 ovarian follicle, the spermatic fluid being apparently introduced into 

 the ovary or abdominal cavity by the male^ which is provided with 

 an intromittent organ consisting of the anal fin much modified, and 

 the spermatozoa find access to the egg through a wide opening in the 

 follicle which answers to a micropyle, but which may be called the 

 follicular pore. (2) There is no evidence, as in the case of Anableps 

 and the Einbiotocidae, that the ovarian follicles are ruptured until the 

 development of the young embryos is approximately completed, since 

 the most advanced foetuses of Gambusia studied have the scales, fins, 

 fin-rays, and cranium remarkably well developed, even before the 

 yolk is all absorbed. (3) Little or no nutriment is derived from the 

 parent, as in Anableps and the Embiotocidfe ; or, in other words, the 

 embryo of Gambusia grows entirely at the expense of the material 

 contained in the yolk-sac, and does not form villi upon the latter nor 

 enlarge after the yolk has been absorbed, as in Anableps ; neither 

 does the rectum or hind-gut hypertrophy, nor do the fins expand and 

 develop prolongations of the interradial membranes as in the Embio- 

 tocidae. (4) As is the case with all viviparous forms, the number of 

 embryos produced seems to be diminished in correlation with the 

 protection which the young receive in consequence of their peculiarly 

 complete development within the body of the parent. VI. Habits of 

 Gambusia during the breeding season. VII. Viviparity of Fundulus. 



Origin of the Spermatozoids in the Seminiferous Canals.* — Dr. 

 D. Biondi has carried out some investigations with the view of throw- 

 ing some light on the origin of the spermatozoids in the seminiferous 

 canals, a question on which the views of physiologists have been 

 widely divergent. By appropriate use of processes of hardening, 

 fixing, and colouring (among which the advantages of Flemming's 

 fluid arc specially mentioned) Dr. Biondi arrived at results which 

 corroborated none of the views formerly put forth, but which ex- 

 plained the earlier observed facts. 



In accordance with these results the author endeavoured to dis- 

 tribute diagrammatically the contents of the seminiferous canals into 

 columns, which, proceeding from the wall towards the central cavity, 

 might bo grouped into three layers. In the first stage of develop- 

 ment, a stage always met with, in particular, in animals not yet 

 mature, tlio oxtremo layer lying on the wall of tlie canal consisted of 

 round primitive colls, which were very rich in karyokinetic figures, 



♦ Berlin Physiol. Soc, 1885, July 31. See Nature, xxxii. (1885) p. 544. 



