Henn: South American Pceciliid Fishes. 99 



been considered members of different genera, were in reality male and 

 female of the same species. He gave no details of the behavior of the 

 two sexes. 



Ryder (1885, p. 155) published a more detailed account of the ac- 

 tions of Gambusia patruelis, based on observations related to him by 

 A. A. Duly, an employee of the National Museum. The head of the 

 male was said to be turned in the direction of the tail of the female 

 during coitus and the prolonged anal fin thrust into the external 

 opening of the ovarian duct. This account, according to the observa- 

 tions of both Philippi and Seal, is entirely wrong. 



Philippi had opportunity to see the copulation in both P. caudo- 

 maculatus and C. decem-maculatiis. The habits of the two species 

 are essentially alike. The anal fin of the male, which normally lies 

 folded against the abdomen, is in breeding males suddenly thrust for- 

 ward and somewhat sidewise. The male slowly follows the female, but 

 maintains a certain distance, going through exactly the same motions 

 as the female. In general the male swims somewhat under and be- 

 hind the female. It suddenly darts upward toward the female, and 

 with extraordinary speed places the tip of the anal bearing a sperm 

 capsule upon the urogenital papilla of the female. With equal speed 

 its course is continued and the anal is withdrawn into the usual posi- 

 tion. 



Seal (191 1, p. 92) observed the breeding habits of Gambusia hol- 

 brooki and Heterandria formosa, which he kept in aquaria. The 

 habits are said to be exactly alike. He says: " The male follows in- 

 cessantly and warily after the female, on the left side and to the rear, 

 the female frequently turning and making savage dives at him, 

 causing him to turn and flee, but to return immediately and follow, 

 watching for a moment when her attention will be distracted, when 

 he will make a sudden dash, sometimes succeeding in inserting the 

 intromittent organ into the genital pore, but of tener apparently missing, 

 because of a quick turn of the female from which he flees in apparent 

 terror. The contact is so sudden and brief that it required many 

 observations to verify it. In these movements the male organ is 

 thrust forward and to the right toward the female. In small jars 

 the males are frequently killed, especially when the female is full sized, 

 or if there are two or three females to one male. . . . There is never 

 more than one male following a female. If others approach, the male 

 turns and drives them off." 



