no Field Columbian Museum — Zoology, Vol. V. 



male with its first 5 or 6 rays short and stiff and separated from 

 the rest of the fin by a shallow notch; dorsal fin of male higher than 

 that of female; viviparous. The ovary is a strong membranous sack, 

 with several infolded partitions; in this the young develop and 

 reach a comparatively large size when they are born, which is during 

 May and June. 



KEY TO THE SPECIES OF ZOOGONETICUS. 



a. Four to six black spots about as large as eye page 



on lower half of caudal peduncle ; 2 similar 



black spots at base of caudal cuitzeoensis no 



aa. No black spots on lower half of caudal pedun- 

 cle; not more than one black spot at base of 

 caudal, 

 b. Sides of body with 7 to 9 well defined black 



bars each about as wide as the interspaces dugesi in 



bb. Sides of body without well-defined cross-bars. 



c. Anal fin longer than the dorsal; dorsal rays 



12 to 14; anal rays 14 to 17. 



d. Scales large, 32 to 35 in the lateral series; 



head very thick and broad, 2>Y> in length; 



dorsal rays 13 or 14; anal rays 15; scales 



1 2-3 5 [pachyccphalns] 112 



dd. Scales smaller, 37 to 39 in the lateral series. 



e. Origin of dorsal fin midway between tip 



of caudal fin and tip of snout; head large, 



3 Y in length ; depth 3 ; dorsal rays 1 4 ; anal 



rays 16 ; scales 16-38 robustus 112 



' ee. Origin of dorsal fin midway between tip 



of caudal fin and opercle maculatus 113 



cc. Anal fin shorter than the dorsal ; dorsal rays 

 17 ; anal rays 14. 

 f . Origin of dorsal fin midway between base of 

 caudal and posterior margin of opercle ; head 



3 % ; depth 3 Y diazi 1 1 4 



ff. Origin of dorsal fin midway between base 

 of caudal and preopercle; head 3-I-; depth 

 3Y miniatus 115 



99. Zoogoneticus cuitzeoensis (B. A. Bean). 



Platypcecilus quitzeoensis B. A. Bean, Proc. U. S. Nat. Mus., 

 1898, 540, fig. 1; Lago de Cuitzeo, Michoacan: Jordan & 

 Evermann, Bull. 47, U. S. Nat. Mus., 189S, 2873. 



