FISHES. 245 



Plate XXXIV, fig. 1, represents Thrichomycterus maculatus, size of life, and in profile, 

 fig. 2 is au outline of the same, seen from above, 

 fig. 3, the head, seen from below. 



THEICHOMYCTERUS MACE^I, Girarfl. 



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 T. 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 T. 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 UspuUata, east side 

 of the Cordilleras, at an elevation of about 7,000 feet. 



FAMILY OF CLUPEID^. 



Genus ALOSA, Cuv. 

 Gen. char. No teeth upon any of the bones constituting the apparatus of the mouth. 



Syn. Alosa, Cuv. Eegn. Anim. (2d ed.) II, 1829. 



Cuv. et Val. Hist. Nat. des Poiss. XX, 1847, 389. 



Obs. 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 coeca. 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. 



