CYPRINODONT FISHES. 997 



3. PCECILIOPSIS PLEUROSPILUS. 



Oirardinus plearosjnltfs Giinth. Cat. J^'ish. vi. p. 355 (1866), 

 and Trans. Zool. Soc. vi. 1868, p. 486, pi. Ixxxvii. fig. 1 ; Regan, 

 Biol. Oentr.-Amer., Pisces, p. 100 (1907). 



Lakes Dueiias and Nacasil in Guatemala. 



4. PCECILIOPSIS RETROPINNA. 



Poecilia retropinna Regan, Ann. Mag. Nat. Hist. (8) ii. 1908, 

 p. 458. 



Costa Rica. 



5. PCECILIOPSIS iSTHMENSis, sp. n. (PI. C. figs. 3, 4 ; and Text- 

 fig. 171 B.) 



5 . Depth of body 2|- to 3 in the length, length of head 3| to 3|. 

 Diameter of eye 3 to 3^ in length of head, interorbital width 

 14 to 2. 26 to 28 scales in a longitudinal series. Dorsal 9-10; 

 origin equidistant from anterior edge of eye and base of caudal ; 

 longest ray |^ length of head. Anal 10 ; origin below fourth or 

 fifth ray of dorsal ; first branched ray longest, | length of head or 

 more. Pectoral a little shorter than head ; pelvics reaching anal. 

 Least depth of caudal peduncle f or | length of head. Olivaceous ; 

 scales dark-edged ; a blackish spot above the vent ; fins dusky, the 

 dorsal with blackish basal band and dark edge. 



c? . Dorsal origin equidistant from tip of snout and base of 

 caudal, or nearer former ; intromittent organ, when laid back, 

 nearly or quite reaching caudal fin ; indistinct cross-bars on body. 



Colon, Panama. 



8 females, 35 to 60 mm. in total length, and 4 males of 35 to 

 42 mm., presented by Herr A. Rachow. 



6. PCECILIOPSIS PITTIERI. 



Pcecilia pittieri Meek, Field Mus. Publ., Zool. x. 1912, p. 71. 

 Closely related to the preceding, but described as with a smaller 

 head and larger eye. 

 La Junta, Costa Rica. 

 Total length 43 to 65 mm., males to 53 mm. 



11. Brachyrhaphis, gen. nov. 



Differs from Gamhusia in the shorter intromittent organ ending 

 in a small retrorse hook formed by the second and third pro- 

 duced rays. 



Brachyrhaphis rhabdophora. (Text-fig. 169 D.) 



Gamhusia rhabdophora Regan, Ann. Mag. Nat. Hist. (8) ii. 

 1908, p. 457. 



Costa Rica, 



Specimens recently received show that in this species the origin 

 of the anal fin may be behind below or in advance of that of the 

 dorsal. 



