Prof. Agassiz on Viviparous Fishes from California. 385 
turns backwards again, and ends in a straight course at the anus. 
The stomach can not at all be distinguished externally from the 
small intestine by its size and form. There are no cecal append- 
ages at all in any part of the intestine. The whole alimentary 
canal contained large numbers of shell fragments of small Mytili. 
The liver has two lobes, a short one on the left side, and a long 
one along the middle line of the body. 
The female genital apparatus, in the state of pregnancy, con- 
sists of a large bag, the appearance of which in the living animal 
has been described by Mr. Jackson; upon the surface of it large 
vascular ramifications are seen, and it is subdivided internally 
into a number of distinct pouches, opening by wide slits into the 
lower part of the sack. This sack seems to be nothing but the 
widened lower end of the ovary, and the pouches within it to be 
formed by the folds of the ovary itself. In each of these pouches a 
young is wrapped up as in a sheet, and all are packed in the most 
economical manner as far as saving space is concerned, some 
having their head turned forwards, and others backwards. This 
opening is situated behind the anus, upon the summit and in the 
centre of a conical protuberance formed by a powerful sphincter, 
kept in its place by two strong transverse muscles attached to 
the abdominal walls. ‘The number of young contained in this 
sack seems to vary. Mr. Jackson counted nineteen; I have 
in proportion to the mother. In a specimen of Emb. Jacksoni, 
103 inches long, and 43 high, the young were nearly three inches 
long and one inch high; and in an Emb. Caryi, eight inches 
long, and 34 high, the young were 23 inches long, and iths 
of an inch high. Judging from their size, I suspected for some- 
time that the young could move in and out of this sack like 
young opossums, but on carefully examining the position of 
the young in the pouches, and also the contracted condition of 
the sphincter at the external orifice of the sexual organs, I re- 
mained satisfied that this could not be the case, and that the 
young Mr. Jackson found so lively after putting them ina bucket 
of salt water, had then for the first time come into free contact 
with the element in which they were soon to live; but at the 
same time, it can hardly be doubtedethat the water penetrates into 
the marsupial sack, since these young have fully developed gills. 
The size of the young compared with that of the mother is very 
remarkable, being full one-third its length in the one, and nearly 
so in the other species. Indeed these young Embiotoce, not yet 
hatched, are three or four times larger than the young of a Pomo- 
tis (of the same size) a full year old. In this respect these fishes 
Srconp Series, Vol. XVI, No. 48.—-Nov. 1853. 49 
