8 University of Michigan 



SJciffia bilineattis Meek, Publ. Field Mus., Zool., 3, 1902, p. 105. 

 Sl-iffla bilineata Meek, Pub. Field Mus., Zool., 5, 1904, p. 144, fig. 45. 

 Goodea bilineata Regan, Biol. Centr.-Am., Pisces, 1908, p. 92. 



Sexual dimorphism has been carried to an extreme in this 

 well-marked species. Four males, 19 to 22 mm. long to the 

 caudal fin, collected by Meek at Huingo, Lake Cuitzeo, Mexico, 

 have been examined. In these the body is more slender than 

 in the female, and the vertical fins are much larger. The black 

 dorsal fin reaches to the base of the upper caudal rays. The 

 highly characteristic color pattern of the female is not devel- 

 oped in the male, only the anterior portion of the main median 

 streak being apparent. In contrast the male has 12 to 20 

 spindle-shaped vertical bars, of greatly varying height, dis- 

 tributed along a line occupied by the lateral band in the 

 female. In both sexes the edges of the caudal peduncle are 

 black. 



5. Skiffia lermae Meek 



Sl-iffia lermae Meek, Pub. Field Mus., Zool., 3, 1902, p. 102, pi. 25; 

 ibid., 5, 1904, p. 142. pi. 8. 



Goodea lermae Eegan, Biol. Centr.-Am., Pisces, 1908, p. 92. 

 ('?)Skiffla variegata Meek, Publ. Field Mus., Zool., 3, 1902, p. 104, 

 pi. 25; ibid., 5, 1904, p. 143, fig. 44. 



The types of Skiffia variegata, from Lake Zirahuen, are 

 similar in form to specimens of like size from Lake Patzcuaro 

 (lermae). They have the same number of fin rays (usually 

 13 in both dorsal and anal fins) and the same number of scales 

 (usually 35 or 36 rows). 



The differences which are apparent involve only the colora- 

 tion. The spots are larger in those from Zirahuen (variegata) 

 than in those from Patzcuaro (lermae), but the spot on the 

 base of the caudal rays is not vertically elongate as in those 

 from Patzcuaro. Those from Chalco resemble '^ variegata" in 

 coloration, while those from Celaya are like typical lermae. 



It remains to be determined, however, whether these color 

 differences are of taxonomic significance. 



