92 Field Columbian Museum— Zoology, Vol. III. 



The females are lighter in color than the males; on the 

 rhiddle of the side of female to the tip of the pectoral are iisuall)^ 

 three faint dark spots, also four to six dark bars on lower half of 

 caudal peduncle, and a dark spot on upper portion of caudal 

 peduncle above the last bar. The color of the males is moVe 

 uniform and much darker; the spots or bars so conspicuous on 

 the female are scarcely noticeable on the male; dorsal and anal 

 tins black, tipped with yellow; caudal and tips of ventrals black- 

 ish; pectorals light, as are all the fins of the female. The first 

 six ravs of anal short, and separated from the rest of the fin by a 

 shallow notch. 



The body of this fish is more compressed and less robust 

 than that of others of this group. Head 3|; depth 3; dorsal rays 

 13 or 14: anal 13 to 15. This species is viviparous. Their 

 young had evidently been born a short time previous to our visit. 



They apparently deposit their j^oung during thi: first half of 

 May. La Barca; Ocotlan. 



Zoogoneticus dugesii (Bean). 



Intestinal canal about equal to length of Dod}-. Peritoneum 

 blackish. 



A few specimens were taken at Patzcuaro and a few at Lagos. 

 Viviparous; one female from Patzcuaro 2.22 inches in length con- 

 tained 32 young; all Avere well formed and with egg absorbed; 

 length of young .16 inch. These are by far smaller than the 

 young from females of other species. 



No males were taken. The longest specimen is from Lagos, 

 2.50 inches. This well marked species is apparently very scarce. 



Patzcuaro specimens taken May 18 to 22: time for spawning 

 evidently last half of May. Lagos: Patzcuaro. 



Zoogoneticus robustus (Bean). 



This is one of the largest Cypn'!iodo?ifs found in Mexico. It is 

 known only from the Lerma Basin. 



The largest specimen in our collection is a female 6.80 inches 

 in length. It was taken in Lake Zirahuen on May 24. 



The color of the few specimens from this lake is very dark. 

 The species is viviparous. One female from Patzcuaro Lake, 

 4.26 inches in length, contained 20 young, each .67 inch in 

 length. These young possess the markings of the smallest 

 specimens collected. 



A second female from Patzcuaro Lake, 4.65 inches in length. 



