944 Ayres's Description of a new Species 
on the connecting membrane but on the rays themselves, one 
to each joint. 
The free finlets of the back are six in number. The first 
arises four inches and one fourth from the anterior extremity 
of the head. "They are of nearly uniform size, from four to 
five tenths of an inch in height. 'The spinous ray which 
forms the anterior border of each is flattened transversely, 
slightly curved, bidentate at summit. The first two are pro- 
vided each with two soft rays springing from the spinous ray, 
the third with three, the other three have each but one. 
The membrane of the first finlet does not extend to that 
which succeeds, and the same is true of the second and 
third; in the fourth and fifth it just reaches to the base, 
while in the sixth the membrane ascends slightly on the 
spinous ray of the seventh. The seventh is so attached to 
the caudal fin as to seem a portion of it, though its structure 
is precisely similar to that of the free finlets; it is provided 
with a single soft ray. 
The caudal fin is slightly heterocireal. It contains sixteen 
‘stout and flattened rays, which present an enamelled surface 
-~ similar to that of the plates covering the body. 
The anal fin is composed of fourteen rays. The first nine 
are united into an apparently solid body without exhibiting 
the connecting membrane except near their extremities. 
This is readily effected from their peculiar shape. Each ray 
is a thin plate, placed transversely, having its sides curved 
backward, and the convex surface of each being closely 
applied to the concavity of the one preceding it, the mem- 
brane which joins them is seen only when they are forcibly 
separated. The last five rays are like those of ordinary 
fishes. The plates of the body at the base of this fin are 
free and extend a little way up its sides, forming a sort of 
sheath. bus 
The ventral fins are placed upon a base similar to that of 
the pectorals, but much shorter. The rays are ten in number, 
resembling those of the caudal fin in structure. 
