384 Prof. Agassiz on Viviparous Fishes from California. 
which respect they differ widely from those fishes they resemble 
most in external appearance. e opercular pieces are without 
spines or serratures. Branchiostegal rays six. The mouth is en- 
circled by rather thick lips; the intermaxillaries forming b 
themselves the whole margin of the upper jaw. The intermax- 
illaries and upper maxillaries are slightly protractile. Teeth only 
upon the intermaxillaries, lower maxillaries and pharyngeals; 
none either upon the palatines or the vomer. In this respect, as 
well as in the absence of spines and serratures upon the opercular 
pieces, they differ much more from the Percoids, than from the 
paroids ; but the cycloid scales remove them at once from the 
latter, in which the scales present a very uniform ctenoid type. 
The thick lips might remind one of the Labroids, but the scales 
of the Embiotoca are neither elongated, nor provided with the 
characteristic branching tubes of that family. 
One long dorsal fin, the anterior portion of which is supported 
by spinous rays, and the posterior by numerous articulated branch- 
ing rays, which are sheathed at the base by two or three rows of 
scales, separated from those of the body by a rather broad and 
deep scaleless furrow. This last peculiarity has not yet been ob- 
served in any fish, as far as I know. There is indeed a distinct 
longitudinal space parallel to the soft portion of the dorsal, nearly of 
the width of a single row of scales, which is entirely naked and 
well defined, forming as it were, a furrow between the scales of 
the back, and those which rest against the base of the fin rays. 
Though protected in this way by a kind of sheath, the anterior 
part of the dorsal fin alone can be folded backwards and en- 
tirely concealed between these scales, as in many Sparoids; the 
posterior part only partially so. Moreover, the scales of the sheath 
are separated by a furrow from those of the back, only along the 
se of the soft part of the dorsal fin. The first rays of the anal 
fin are short, comparatively small and spinous. ‘The base of this 
fin is strangely arched, and sheathed between scales, in the same 
manner as the dorsal ; the spinous rays when folded back being 
more fully concealed in the sheath than the soft rays. 
The ventrals are subthoracic as in the Sparoids, and provided 
with a strong spinous and five soft rays. : 
“our branchial arches, supporting four complete branchie with 
two rows of lamelle in each. The opening behind the last arch 
is very small and entirely above the base of the pectoral fins. 
Pseudobranchia very large, and composed of sixteen or seventeen 
lamelle. The alimentary canal is remarkably uniform in width for 
its whole length. It extends first on the left side as far back as 
the ventrals, turns forwards and upwards to the right, then follows 
the middle line along the large air bladder, to the seconc third 
of the abdominal cavity, then bends along the right side down- 
ward and slightly forwards almost to meet the fi 
