the Development of Anableps Gronovii. 431 
it, to be visible. Externally, the sac is covered with what 
appear to be parallel projecting lines, extending from the 
sides of the abdomen to its most prominent part (Figs. 6 
& 8.) These Valenciennes describes as “vascular striæ,” 
(stries vasculiformes.*) Such was not the nature of these 
markings in the specimens which I examined; but, when 
placed under the microscope, were found to form a peculiar 
structure, which possibly may have some connection with the 
process of nutrition in their peculiar method of gestation. 
The sac itself seemed nearly homogeneous in structure, 
but the striæ are made up of spherical, or in some cases, pyri- 
form or cylindrical, papillæ or villi, (Fig. 8,) projecting from the 
surface, and arranged so nearly together in a linear series as to 
give the appearance of a continuous band. In regard to the 
minute structure of these papille, as far as it could be deter- 
mined from an alcoholic specimen, they consist externally of 
an exceedingly thin membrane, inclosing a vast number 
of minute granules; no vessels were seen in connection 
With them nor in the membrane to which they were attached. 
There was no appearance of any communication between the 
cavity of the papilla and that of the membrane to which it was 
attached. Within the latter, but more nearly in contact with 
the intestines, there was a second more delicate ‘membrane, 
Which seemed to be a continuation of the parietal peritoneum. 
No traces of the yelk were found in connection with the 
intestines, 
. HI. The third specimen is much longer and measures ten 
inches in length ; the ovary had been ruptured, so that some 
of the fetuses had escaped into the cavity of the abdomen, 
but the whole number of young taken from the parent was 
much greater than in the preceding case, namely, eighteen ; 
one of these was projecting from the genital opening. ‘They 
Senerally resembled the preceding except in size, though the 
eyes had become more prominent (Fig. 6,) and the iris now 
/.* Op. cit. ex fol. de planche, 539. 
