248 MR. C. TATE REGAN ON THE 



6. Chjstostomus deemoehvnchus. 



Chmtostomus dermorhynchus Bouleng. Proc. Zool. Soc. 1887., p. 277, pi. xxii. 



Depth of body 4f-5 times in the total length, length of head 3-3^ times. Head as 

 broad as long and 1-f-lf times as long as deep. Diameter of eye 6-8 times in the 

 length of head, interorbital width 3-3^ times, length of snout 1|— If times. Length 

 of mandibular ramus equal to or a little greater than the interorbital width. Inter- 

 operculum armed with 4 or 5 short spines. 24 scutes in a longitudinal series, 

 6 between dorsal and adipose fin, 10 between anal and caudal. D. I 8 (rarely I 9), 

 the first ray equal to |- the length of head, the last f-f as long; length of base 

 of dorsal equal to its distance from posterior part of spine of adipose fin. A. I 5 

 (rarely I 4). Pectoral spine extending a little or considerably beyond the base of 

 ventral. Caudal peduncle twice as long as deep. Olivaceous, some dark spots on 

 the head, a few series of dark or light spots on the sides of tne body ; dorsal with 

 dark or light spots on the rays and a dark spot at the base of the first interradial 

 membrane. 



Total length 250 mm. 



Six specimens from E. Ecuador. 



7. fCniETOSTOMUS FISCHERI. 



Chcetostomus fischeri Steincl. Denkschr. Ak. Wien, xli. 1879, p. 164, pi. iv. fig. 9. 



Depth of body 5f— 5f times in the total length, length of head 3^-3^ times. Head 

 as broad as long and If times as long as deep. Diameter of eye 8-8^ times in the 

 length of head, interorbital width 3-3^ times, length of snout 1^-lf times. Inter- 

 operculum armed with 1-2 spines. 23-24 scutes in a longitudinal series, 6-7 between 

 dorsal and adipose fin, 10-11 between anal and caudal. D. I 8, the first ray equal to 

 -f- the length of head, the last f as long ; length of base of dorsal equal to its distance 

 from the posterior \ of the spine of the adipose fin. A. I 5. Pectoral spine extending 

 to middle of ventral. Caudal obliquely and slightly emarginate. Caudal peduncle 

 about 2^ times as long as deep. Little yellowish dots on the head and anterior 

 part of body ; fins spotted or clouded with blackish. 



The types, from the Rio Mamoni, near Chepo, measure up to 275 mm. in total 

 length. 



8. fCH^ETOSTOMUS STANNII. 



Chcetostomus stannii Liitk. Vid. Medd. 1874, p. 209 ; Steind. Denkschr. Ak. Wien, xliii. 1881, 

 p. 120, pi. v. fig. 4. 



Very closely allied to the preceding species, with which it agrees in the form and 

 proportions of head and body and the number of scutes and fin-rays, but with a 



