FISHES. 41 
Plate XXXIV, fig. 1, represents Thrichomycterus maculatus, size of life, and in profile. 
fig. 2 is an outline of the same, seen from above. 
fig. 8, the head, seen from below. 
THRICHOMYCTERUS MACRAI, Girard. 
Spec. cHar. General aspect elongated, subfusiform; peduncle of tail long and slender. Dor- 
sal fin elongated, and quite low posteriorly. Anal fin narrow. Ventrals and pectorals rather 
small. Caudal posteriorly emarginated. Ground-color greenish brown, with small, pavement- 
like blackish spots extending all over the body. 
Descr. The general form resembles that of 7. maculatus; the peduncle of the tail is still more 
slender, and the posterior edge of the caudal subcrescentic, with the inferior lobe larger than the 
upper lobe, The head is contained nearly six times and a half in the total length, which meas- 
ures four inches and a half. The base of the dorsal fin is contained three times in the distance 
between its anterior margin and the extremity of the snout, and once between its posterior mar- 
gin and the base of the caudal; the latter fin being one fourth shorter. The anterior third 
of said dorsal fin is higher than the remaining portion, which is comparatively very low. The 
origin of the anal takes place opposite the middle of the length of the dorsal ; it is deeper than 
long, and rounded upon its external margin, which extends backwards almost evenly with the 
posterior margin of the dorsal. The ventrals and pectorals are short and rounded exteriorly. 
The buccal and nasal tentacles are shorter than in 7. maculatus. The prickles about the oper- 
cular apparatus are but little conspicuous. The head is broad and depressed ; the mouth is 
moderately developed. 
The ground-color is greenish or yellowish brown ; the upper regions are covered with numer- 
ous small blackish spots, assuming a tessellated or else a pavement-like aspect. Beneath, the 
color is uniform yellowish or greyish. The fins present the same tint, with a blackish hue 
towards their margin. 
Three specimens of this species were collected by Lieutenant MacRae near Uspullata, east side 
of the cordilleras, at an elevation of about 7,000 feet. 
FAMILY OF CLUPEIDZ. 
Genus ALOSA, Cuv. 
Gen. cHaR. No teeth upon any of the bones constituting the apparatus of the mouth. 
Syv. dlosa, Cuv. Régn. Anim. (2d ed.) II, 1829. 
Cuv. et Vat. Hist. Nat. des Poiss. XX, 1847, 389. 
Oxs. The total absence of teeth in this genus will readily distinguish it from any other of the 
same family. It is here admitted as characterized in the ‘‘ Histoire Naturelle des Poissons.”’ 
The species resemble the herrings in their general appearance; the stomach being rather 
large and acute, and the pylorus provided with numerous ceca. The intestine likewise folds 
twice upon itself. The air-bladder is large, attenuated at both extremities, swollen upon its 
middle region, and communicating with the stomach ; its anterior extremity not extending 
beyond the third vertebra. 
