FISHES. 33 
pectorals, and their tips extend further backwards. Their spiny ray is well developed, and 
the central soft ones bifurcate three times upon their length. The pectorals are short, and 
rounded when expanded, composed of slender rays which bifurcate only twice. 
Bree V— Vel DEX, i A Si Cra Say. ess) Vole oe 14 
The scales are large, provided posteriorly with slender and filiform serratures. They are * 
higher than long, anteriorly subtruncated, and rounded upon the other sides of their outline. 
Four longitudinal rows are observed between the anterior dorsal and the lateral line, and about 
twelve rows beneath, between the latter and the middle line of the belly. They diminish in 
size towards the occiput and nape, as well as towards the inferior surface of the body. The 
largest may be seen upon the middle of the flanks. The upper surface of the head is nacked 
and perfectly smooth. Small scales exist on the cheeks, and somewhat larger ones on the 
opercular apparatus. The suborbitals and the maxillary are scaleless. The lateral line, in 
which there are about thirty-five scales, from the upper part of the opercle to opposite the mid- 
dle region of the second dorsal fin, constitutes a depressed and occasionally somewhat undula- 
ting arch ; then runs nearly straight towards the base of the caudal fin. 
The ground-color assumes either a light reddish or reddish brown hue. The head, dorsal 
region, and sides of body and tail, are irregularly blotched with blackish or deep brown—the 
blotches being the result of an accumulation of minute dots. The lower surface of the head 
and throat are sown over with similar dots sometimes disposed in irregular streaks. The 
ground-color of the fins is light yellowish, the rays made blackish by crowded dots ; the pecto- 
rals and ventrals less so than the dorsals, caudal, and anal. 
Inhabits the Rio de Maypu; specimens were obtained from an affluent of that river, in the 
vicinity of Santiago. 
Plate XXIX, fig. 5, represents the profile of Percilia gillissii, size of life, 
fig. 6 is an outline, viewed from above. 
fig. 7, a scale of the dorsal region. 
fig. 8, a scale of the lateral line. 
fig. 9, a scale of the abdominal region. 
Figs. 7, 8, and 9 are magnified. 
- FAMILY OF ATHERINIDZ., 
The study of this family, heretofore composed of the single genus Atherina, has led us to 
establish several new genera in which the rather numerous species are grouped according to 
several structural peculiarities which, though apparently inappreciable on account of their 
moderate development, are not to be altogether overlooked. 
The genus ATHERINOPsIS is to receive such species in which there are no palatine teeth, with 
both jaws equal, and the snout more or less rounded. 
Atherina menidia, Linn., and Atherina notata, Mrrcu., will find a place in this genus along- 
side with Atherinopsis californiensis, GRD. 
The genus Bastiicutuys will be characterized by the protrusion of the upper jaw beyond the 
lower one. There are no teeth on the palate. 
To this must be referred : 
1°. Atherina microlepidota, JuN., from the fresh waters of Chile, described further on. | 
2°. Atherina laticlavia, Cuv. and Vau.,* from the coast of Chile, and easily distinguished by 
its large scales and its broad silvery lateral band. 
3°. Atherina argentinensis, Cuv. and Vau., observed at the mouth of the Rio La Plata and 
Bay of Maldonado, and commonly known as Pescadilla del rey. 
Hist Nat. des Poiss. X, 1835, 473. 
