438 Wyman's Observations on 
exhibited its lateral projections sufficiently developed to give 
the pupil the shape of a dumb-bell. The umbilical sac has 
become much larger than in the embryos first described; and 
measures three eighths of an inch in diameter. "The papille 
of the yelk-sac are much more distinct and contain colored 
granules. The yelk-sac communicates with the cavity of the 
abdomen by a long fissure extending from a point just behind 
the union of the opercula nearly as far as the anal opening, 
consequently beyond the ventral fins. It is from the circum- 
stance just mentioned, doubtless, that an explanation is to be 
found of the non-union of the ventrals in the adult. The - 
scales terminate abruptly at the edge of the fissure. The 
intestines, as in the first described embryos, were invested by 
the internal sac, which was regarded as parietal peritoneum. 
No bands were visible on the flanks of the body nor were the 
anal fins yet modified to mark the sexes, A rudimentary 
liver is visible in these specimens, extending backwards on 
the left side of the intestinal mass. The intestinal canal is of 
almost uniform size throughout, there being no distinction 
* between intestine and stomach. 
IV. This specimen measured a little less than ten inches 
in length, but the embryos were of much larger size, having @ 
length of two and a quarter inches; the umbilical sac had 
disappeared, (Fig. 7,) but the fissure on the under side of the 
abdomen still remained, and what seems quite remarkable, 
had grown in dimensions just in proportion to the entire 
fetus, so that in these specimens it measured one inch » 
length, and was consequently longer than the whole embryo 
of the first specimen noticed above. The edges of the fissure 
were united by the intermedium of a thin membrane; without 
scales, on which no papillæ were noticed, and was suffi- 
ciently lax to allow the edges of the fissure to separate from 
each other to a slight extent. The transverse band upon p 
cornea was now distinct, though it had not yet become as 
opaque as in the adult. 
Seven fcetuses were found in the ovary; on the sides of 
