130 Annals of the Carnegie Museum. 



Anal of the male a long intromittent organ, inserted below the 

 pectorals. Its length is about 1.7 that of the head. First and second 

 anal rays minute; third, fourth, fifth, and sixth, prolonged. Fourth 

 ray terminating in a point, immediately ventral to this, a single long 

 sickle, or hook. Fifth ray bearing near its upturned tip a series of 

 retrorse hooks. Sixth ray bending ventrally; near its tip a sharp 

 recurved spine. Other rays successively shorter. 



Garman based this genus on immature males, the anals of which 

 were plain sword-like organs without hooks. A good figure of the 

 male anal of Cnesterodon is given by Philippi, Zool. Jahrb., XVII, 

 1908, p. 19, fig. B. 



Phalloceros differs from this genus by the possession of two much 

 smaller hooks or antler-like processes. 



24. Cnesterodon decem-maculatus (Jenyns). 



Poecilia decem-maculatus Jenyns, Beagle Zool., Fishes, 1842, p. 115 (Maldonado). 



Girardinus decem-maculatus Boulenger, Boll. Mus. Torino., X, No. 196, 1895, p. 3 

 (Buenos Aires); Lahille, Revista Mus. de la Plata, VI, 1895, p. 275 (La Plata); 

 Boulenger, Boll. Mus. Torino, XII, No. 279, 1897, p. 4 (Caiza, Bolivian Chaco.) 



Cnesterodon decem-maculatus Garman, Mem. Mus. Comp. Zool., XIX, (i), 1895, 

 p. 44, pi. V, fig. 13, teeth; pi. VIII, fig. 16, male (Uruguay River, Maldonado); 

 Berg, Ann. Mus. Nac. Buenos Aires, V, 1897, p. 290 (Argentina, Uruguay, 

 Brazil); Evermann & Kendall, Proc. U. S. Nat. Mus., XXXI, 1906, p. 90 

 (Argentina); Eigenmann, Proc. U. S. Nat. Mus., XXXII, 1907, p. 431 (Rio 

 Grande do Sul); Eigenmann, Repts. Princeton Univ. Exp. Patagonia, III, 

 1910, p. 458; Regan, Proc. Zool. Soc. London, 1913, p. 1000, fig. 172 B. 



Glaridichlhys decem-maculatus Philippl Zool. Jahrb., XVII, 1908, pp. 10 et seq. 



Cnesterodon carnegiei Haseman, Ann. Carnegie Mus., VII, 1911, p. 385, pi. 

 LXXXIII (Serrinha Parana, Rio Iguassii). 



4661, C. M. Three; two males, one female. 18-22 mm. Cacequy, 

 Rio Ibicuhy, Rio Grande do Sul. 



4662, C. M. Two; male and female. 19-20 mm. Monte, Argentina. 

 The following description is based upon paratypes of Cnesterodon 



carnegiei Haseman, which seems to be identical with C. decem-maculatus. 



Head 4.2-4.8; equal to depth at origin of dorsal; depth of caudal 

 peduncle 7.5-8.6 in length; caudal peduncle about 1.5 in head. Snout 

 short and blunt; mouth oblique; snout 1.2 in eye. Eye medium; 

 3-3.5 in head. 



A male has the head 5; depth at origin of dorsal 5; caudal peduncle 

 7.1 in length and 1.4 in head. 



D. 8-9; A. 9-10; P. 10; V. 4-5; scales 28-31 in lateral line series; 

 8-9 in transverse series. 



