500 Mr. C. T. Regan — A R^^vision 



ocellus (?) or with rather broad pale lower edge and dark 

 intramarginal stripe {^). 

 Southern Mexico. 



1-2. 30-40 mm. Coaxacoalcos. Arnold. 



. 3. 40 mm. „ Bartscb. 



8. llivulus flabellicauda. 



Rivuliis fabellicamla, Eegaii, Aim. & Maj^. Nat. Hist. (7) xix. 1907, 

 p. (34 ; Biologia Cenir.-Am., Pisces, p. 81, pi. x. fig. G (1907). 



Depth of body 4^ in the length, length of head 3^. Head 

 broader than deep. Diameter of eye 3|^ to 4 in the length 

 of head. 40 to 42 scales in a longitudinal, series. Dorsal 

 9-10 ; origin above posterior part of anal, twice as distant 

 from preeoperculum as from base of caudal fin. Anal 12-14, 

 ending below middle of dorsal. Pectoral | the length of 

 head ; pelvics just reaching vent. Brownish ; scales dark- 

 edged ; vertical fins with small spots • a caudal ocellus. 



Costa Rica. 



1 (type). 70 mm. Juan Virias. Underwood. 



2. 30 mm. San Jose. Biolley. 



9. Eivulus cylindraceus. 



Rlvulus cylindrucetts, Poey, Mem. Cub. ii. 1801. p. 308 ; An. Soc. Esp. 



V. 1876, p. 140, pi. V. fig. 4, and ix. 18S0, p. 247, pi. viii. fig. 1 ; 



Giintli. Cat. Fish. vi. p. 327 (1866) ; Garman, Mem. Mus. Comp. 



Zool. xix. 1897, p. 134. 

 Rivulus marmoratits, Poey, Ann. Soc. Esp. ix. 1880, p. 248. 



Depth of body about 4^ in the length, length of head S^. 

 Head broader than deep. Diameter of eye 4| in length of 

 head. 38 or 39 scales in a longitudinal series. Dorsal 10-11 ; 

 origin over middle of anal, twice as far from occiput as from 

 base of caudal. Anal 13, extending back nearly as far as 

 dorsal. Olivaceous, uniform or marbled ; centres of scales 

 darker ; a caudal ocellus. 



Cuba. 



Total length 45 mm. 



10. Rivulus micropus. 



Fundulus micropus, Steiud. Sitzungsb. Akad. Wien, xlviii. 1863, 

 p. 184. 



Depth of body about 5 in the length, length of head about 

 4^ (5| in total). Head broader than deep. Diameter 

 of eye 4 in length of head. 41 scales in a longitudinal 

 series. Dorsal 9 ; origin .2^ head-lengths from gill-opening. 

 Anal 14, ending somewhat before the end of dorsal. 



