*( (t 



tt ft 



tl t( 



2O6 CARL L. HUBBS. 



appears particularly significant, in view of the fact that the 

 females become pregnant at or immediately after their first winter. 

 As usual in fishes, their is no evidence that the growth ever 

 wholly ceases during life, although it is markedly and increasingly 

 retarded with age. 



The growth of the single four-year-old male of Amphigonop- 

 terus obtained near Piedras Blancas was computed from the 

 direct ratio of scale length to fish length. The length of the head 

 and body to the end of the formation of each annulus was thus 

 estimated to have been as indicated below. 



Length at end of formation of natal annulus 26 mm. 



first winter annulus 50 mm. 



" second winter annulus 63 mm. 



third winter annulus 73 mm. 



" " " " " fourth winter annulus 84 mm. 



" " " fourth year (on June 4, 1916) 89 mm. 



The growth of this male, although slower, was quite similar 

 to that of the females, being greater between birth in the summer 

 and the first winter, than during any subsequent whole year; the 

 check in growth rate in this case follows the second, rather than 

 as usual the first, period of breeding. 



The writer has found but one published record of a direct 

 observation on the rate of growth of a viviparous perch. It was 

 made on aquarium fishes by the late Charles Frederick Holder, 

 and published anonymously and without identification of species. 1 

 The obscure but pertinent passage is as follows. " The young, 

 ten or twenty in number, born in the summer, are from an inch 

 and a half long at birtri, and attain half their adult size the first 

 winter, and their full growth in about two and a half or three 

 years." Dr. Eigenmann (1894) has remarked on the large size 

 of the smaller breeding females of Cymatogastcr, which he cor- 

 rectly assumed to be one year old. A similar rate of growth 

 holds in the case of Micrometrus minimus. 



In the course of his extensive investigations of the life-history 

 of the sockeye salmon (Oncorhynchus ncrka) , Dr. C. H. Gilbert 



i Another note by the same author makes it evident that the species ob- 

 served was Cymatogaster aggregatus (see Bull. U. S. Bur. Fish., Vol. 28, 1908 

 (1910), p. 1139). 



