LIFE-HISTORY OF AMPHIGONOPTERUS AURORA. 189 



transforming spermatids and spermatozoa appear most .abundant 

 (Fig. 3) : the testes, as well as the gland on the anal fin, are a; 

 well developed in these newly born males, as in the one-, two- 

 and four-year-old males obtained during the breeding season. 

 Both the primary and secondary sexual structures become greatly 

 reduced in size during the autumn, winter and spring of the first, 

 as of the succeeding years. In fact two young males only a few 

 millimeters longer than the birth stage, collected in June, were 

 already " spent." The writer has further determined that the 

 testis becomes similarly enlarged in Micrometrus minimus and in 

 Cymatogaster aggrcgatus just before birth. No evidence was 

 obtained, however, to indicate that the males of Embiotoca later- 

 alls are mature at birth ; even the two one-year-old males of this 

 species (in and 116 mm. long to caudal) obtained near Pt. Sal, 

 in California, on June 17, with breeding females, were immature. 

 It is quite possible that the natal maturity of the males is con- 

 fined to the smaller species of the Embiotocidse. 



This natal maturity of the males is particularly significant in 

 view of the fact that the females bear young first at the age of 

 one year. This phenomenon, while unique in the whole class of 

 fishes, so far as the writer is aware, finds a physiological parallel 

 in protandric hermaphroditism, in the frequent early maturing 

 of the male (the "grilse") in the Salmonidse, and in the earlier 

 seasonal activities of the males of many animals. 



COPULATION, AND THE STORAGE OF SPERMATOZOA. 



Dr. Eigenmann (1894, p. 420) summarized one phase of his 

 studies of another viviparous perch with this statement : " Copu- 

 lation takes place in Cymatogaster during June or early July, 

 although the eggs are not fertilized till the following December." 

 He based this conclusion firstly on observations on the seasonal 

 activities of the two sexes, and on the seasonal development of 

 the testes in the male, and secondly, on the discovery of the 

 presence of spermatozoa in the oviduct and in the ovarian folds 

 of the female, during the latter part of the summer, and the 

 autumn. The writer has been able to extend this evidence by the 

 first observation of the copulation of this, in fact of any, embio- 

 tocid. The female of the pair in question upon capture was 



