Fishes from Mexico and British Honduras. 257 



is 4-4^ times in the length of head, interorbital width 2|-2§ 

 times. Mouth moderate, oblique, the lower jaw prominent. 

 Sc. 36-38. D. 13-14, its origin about equidistant from 

 posterior edge of prseoperculum and base of caudal, its longest 

 raj (the fourth or fifth) a little longer than the base of the 

 fin, which is ^ the length of head or less. A. 15, commencing 

 a little behind the dorsal, the first six ra}'s, in the male, short, 

 stiff, and of equal length. Pectoral §— § the length of head. 

 Ventrals extending to the vent. Caudal truncate. Caudal 

 peduncle l§-2 times as long as deep. Brownish above, 

 silvery below, with dark spots which are most conspicuous 

 posteriorly ; fins immaculate. 

 Total length 84 mm. 



Three specimens from the Rio Santiago, Mexico, collected 

 by Dr. A.C. Buller. 



Z. pachycephalia, Gthr., and the very closely allied 

 Z. quitzeoensis and Z. robustus of Bean, agree with this species 

 in the number of dorsal and anal rays, but have a shorter 

 and broader head and the caudal peduncle about as long 

 as deep. 



Dr. Meek includes Fundulus guatemalensis, Gthr., and 

 F. labialis, Gthr., in Zoogoneticus, but in neither of them is 

 there any differentiation of the anterior anal rays in the male. 

 In the former the anal fin is similar in both sexes, in the 

 latter it is larger in the female, and from the specimens in 

 the British Museum one would judge that these species are 

 not viviparous. 



Characodon Oeddesi, sp. n. 



Depth of body 2 §-3 (males) or about 2£ (pregnant females) 

 times in the total length, length of head 3f-4 times. Snout 

 as long as eye, the diameter of which is 4-4£ times in the 

 length of head, interorbital width about 2£ times. About 

 17 rather short gill-rakers on anterior arch. Sc. 39-42. 

 D. 18-20, its origin nearly equidistant from posterior margin 

 of operculum and base of caudal. A. 21-23, commencing a 

 little behind the dorsal, not modified in the male. Pectoral 

 nearly § length of head. Ventrals extending to the vent. 

 Caudal truncate. Caudal peduncle 1^-lf times as long as 

 deep. Olivaceous, silvery below, with several darker narrow 

 vertical bands on the upper half of the body. 



Total length 70 mm. 



Numerous examples of this viviparous species from Lake 

 Tezcoco, Southern Mexico, collected by Mr. P. Gedde3. 



Ann. & Mag. N. Hist. Ser. 7. Vol. xiii. 17 



