152 OSTARIOPHYSI. 
than eye, the diameter of which is 42 to 5 in the length of head ; interorbital width 23 to 3 in the length 
of head. 10 gill-rakers on the lower part of the anterior arch. 65 to 76 scales in a longitudinal series, 
13 to 16 in a transverse series from dorsal fin to lateral line, 8 to 11 between latera] line and base of 
ventral fin. Dorsal 9, with 7 branched rays; origin equidistant from tip of snout and base of caudal or 
slightly nearer the latter ; free edge straight ; longest ray 3 the length of head. Anal 8, with 6 branched 
rays. Pectoral § the length of head, not reaching the ventrals, which are inserted below the origin of 
the dorsal. Traces of a dark lateral band ending in a caudal spot. 
Hab. Mexico, Rio Lerma and upper tributaries of the Rio Panuco!. 
Here described from several specimiens, 90 to 120 mm. in total length, from Aguas 
Calientes (Jordan), Salamanca (Woolman), and San Juan del Rio (Meek). 
This species has a shorter head and larger eye than A. ¢incella, but is especially 
distinguished by the fewer scales between the lateral line and the ventral fin. 
3. Algansea stigmatura, sp.n. (Tab. XXV. fig. 2.) 
Depth of body 4 to 44 in the length, length of head 33 to 4. Snout as long as eye, the diameter of which is 
4 in the length of head ; interorbital width 2? to 3 in the length of head. 13 or 14 gill-rakers on the 
lower part of the anterior arch. 60 to 66 scales in a longitudinal series, 13 to 15 in a transverse series 
from origin of dorsal to lateral line, 7 or 8 between lateral line and base of ventral fin. Dorsal 9, with 
7 branched rays ; origin equidistant from tip of snout and base of caudal; free edge straight ; longest 
ray 3 the length of head. Anal 8. Pectoral 2 the length of head, not reaching the ventrals, which are 
inserted nearly below the origin of dorsal. Silvery; a dark caudal spot. 
Ilab. Muxico, Rio Grande de Santiago. 
Four specimens, 55 to 75 mm. in total length, collected by Dr. A. C. Buller. 
4, Algansea dugesi. 
Algansea dugesi, Bean, Proc. U.S. Nat. Mus. 1892, p. 283, t. 44. fig. 11; Jord. & Everm. Bull. 
U.S. Nat. Mus. xlvii. 1896, p. 2127, and 1900, fig. 98°; Meek, Publ. Columbian Mus., 
Zool. v. 1904, p. 45, fig. 8°. 
Algansea lacustris, Steind. Denkschr. Ak. Wien, Iii, 1895, p. 526, t. 3. fig. 1°; Meek, t. c. p. 47°. 
Algansea tarascorum, Steind. t. c. p. 527, t. 3. fig. 2". 
? Algansea rubescens, Meek, t.c. p. 46, fig. 9°. 
Depth of body nearly equal to the length of head, which is 33 to 4 in the length of the fish. Snout longer 
than eye, the diameter of which is 44 to 6 in the length of head ; interorbital width 3 in the length of 
head. 15 to 17 gill-rakers on the lower part of the anterior arch. 76 to 86 scales in a longitudinal 
series, 18 to 21 between dorsal fin and lateral line, 12 to 15 between lateral line and root of ventral. 
Dorsal 9, with 7 branched rays; origin equidistant from tip of snout and base of caudal or a little nearer 
the latter; free edge straight ; longest ray } to 2 the length of head. Anal 8, with 6 branched rays. 
Pectoral 3 to 3 the length of head, not reaching the ventrals, which are inserted nearly below the origin 
of dorsal. Silvery, back darker ; young with a dark spot at the base of caudal. 
Hab. Mexico, Rio Lerma System: 
Lake Yuriria in Guanajuato!; Lake Chapala in Jalisco®; Lake Patzcuaro in 
Michoacan 4° °7, 
Here described from three specimens, 100 to 200 mm. in total length, from 
