222 L. Agassiz on 
blunter than those of the jaws, and arranged like pavement. 
Dorsal fin with nine or more spinous rays. The first three rays 
of the anal fin spinous, and much shorter than the following 
articulated rays, which are always finer and more numerous 
than the corresponding rays of the dorsal fin. The lateral 
line is continuous to the base of the caudal fin. Whether 
the peculiar mode of reproduction is a family or a generic 
character, remains to be ascertained by further investigations. 
It is, however, probable that with some slight modifications it 
will be found the same in all the members of the family. 
Some differences between the two species observed might 
render it doubtful whether they ought to be considered as 
belonging to as many distinct genera or not. But we know 
that in genera differing greatly from others, the range of the 
Specific differences is also wider than in genera with many 
species ; so until I am taught differently by new discoveries, 
I would refer them both to one and the same genus. Such 
doubts could scarcely be entertained respecting families with 
many genera, where a standard to estimate genuine generic 
differences is easily obtained. 
1. Embiotoca Jacksoni, Agass.—The body is quite high, 
of an oval form, greatly compressed, and similarly arched 
above and below. The superior arch extends to the pos- 
terior base of the dorsal fin, whence it continues in a 
horizontal line to the base of the tail. The ventral arch 
of the body is similar to that of the dorsal outline. The 
profile from the dorsal fin to the end of the snout is rather 
precipitate and regularly arched, except obliquely above 
and in front of the eyes, where it is slightly concave. The 
greatest height of the body, including the dorsal fin, is 
equal to the distance from the end of the snout to the ex- 
tremity of the pectoral. The greatest thickness of the body 
is equal to one-fourth its height. The head is of moderate 
size,—its length, measuring to the posterior angle of the 
opercle, being about one-fourth that. of the entire fish. The 
mouth is quite small,—the hind extremities of the intermaxil- 
laries and maxillaries extending not farther back than the 
line of the orbit. But a small portion of the superior 
