LXVIII BIOLOGICAL SOCIETY OF WASHINGTON. 



ROUS MINNOWS.* The species under discussion was the form known 

 as Gambusia patruelis, B. & G. The points which were especially 

 alluded to were the following : The fact that the young fish devel 

 oped within the body of the female parent and within the follicles 

 in which the eggs themselves were developed. It was also pointed 

 out that these follicles, which were covered with a rich net-work of 

 fine capillary vessels, assumed the office of a respiratory apparatus, 

 by which the gases were interchanged between the embryo and the 

 parent fish ; and, further, that this follicle also acted as an egg 

 membrane, being actually perforated by a round opening, which 

 the speaker termed the " follicular pore," and which was analogous 

 to the micropyle of the ordinary fish egg. The arrangement of the 

 follicles of the ovary within the body of the female was described 

 at some length, and the peculiar differences between the two sexes 

 in the arrangement of the viscera were pointed out. The fibrous 

 bands, which act as supports, or stays, to the basal portion of the 

 anal fin of the male, which is modified as an intromittent organ, 

 were also described. The great difference in the sizes of the sexes 

 was also referred to, the female weighing over six times as much as 

 the male. The speaker concluded by expressing his earnest desire 

 to investigate the other known forms of viviparous fishes, such as 

 the Embiotocoids of the West coast, the viviparous Blenny, and 

 other bony fishes which have this habit, and which, in his opinion, 

 would throw considerable light upon some of the peculiar physio 

 logical processes involved in the viviparous methods of develop 

 ment. 



Mr. Romyn Hitchcock exhibited a collection of Foraminifera 

 belonging to the genus Lagena, and made a few remarks explain 

 ing the relation between this genus and the Nodosarine group ; 

 these briefly being that Lagena may be taken as the type of the 

 group, passing through Nodosaria and ending in Cristellaria as the 

 most complete manifestation of its method of growth. 



* 1882. RYDER, JOHN A. Structure and ovarian incubation of Gambusia 

 patruelis, a top-minnow. <^ American Naturalist, Feb., 1882, pp. 109-118. 



