318 
fewer scales, and somewhat modified coloration. Nevertheless, we 
should be obliged to refer these snakes to different genera, if we were 
to adopt the dentition as the chief systematic principle: namely, 
L. annulata to Dipsas, L. torquata to Liophis, and L. discolor to 
Coronella. 
PISCES. 
CHROMIS NEBULIFERA, Sp. Nov. 
p.2. A.3. V.1/5. L. lat. 35. LL. transv. 6/13. 
Mouth narrow, protractile ; teeth of the jaws cardiform, in a short 
band, those of the outer series larger, somewhat compressed, brown 
at the tip; palate smooth. Opercles scaly; przeopercular margin 
entire. Nostril simple. 
The height of the body is contained three times and one-half in 
the total length, the length of the head four times and two-thirds. 
The interorbital space is convex, and its width rather more than the 
diameter of the eye, which is one-half the length of the snout. There 
are six series of small scales between the preeorbital and the angle of 
the preeoperculum. The dorsal fin and the lateral line commence on 
the same vertical; caudal truncated; the commencement of the anal 
falls vertically below the sixteenth dorsal spine ; the ventral is inserted 
behind the pectoral, and extends on to the vent. Greenish, the 
middle of the body clouded with blackish, in form of indistinct ver- 
tical bands; a round black spot at the root of the caudal; the outer 
parts of the fins blackish. 
This species would be placed in the genus Heros of Heckel. 
Hab. Fresh waters of Mexico. 
in. lin 
Rata tempt iia a ciF2 ee. oes os we See on hes. 
Eistbht of tim body) e900) Os. Sede is 28 
Length of the head ......... ; Lag 
Diameter of the eye. 0 35 
CHROMIS FENESTRATA, 0. sp. 
DY. ALS. Vi 1/5. L, lat. 33. L. transy. 6/13. 
Mouth narrow, protractile ; teeth of the jaws cardiform, in a short 
band ; those of the outer series larger, somewhat compressed, brown 
at the tip; palate smooth. Opercles scaly; preeopercular margin 
entire. Nostril simple. 
The height of the body is contained two and three-fifth times in 
the total length ; the length of the head four times. The interorbital 
space is convex, and its width more than the diameter of the eye, 
which is one-half the length of the snout. There are five series of 
scales between the preorbital and the angle of the preoperculum. 
The dorsal fin and the lateral line commence on the same vertical ; 
caudal truncated; the commencement of the anal falls vertically 
below the fifteenth dorsal spine ; the ventral is inserted behind the 
