198 



CARL L. HUBBS. 



their course, along a line parallel with the scale margin (cf. par- 

 ticularly Taylor, 1914) / The reason for the formation of this 

 type of annulus is the fact that the circuli toward the end of each 

 year's growth gradually become more strongly curved, whereas 

 those marking the new growth are straighten This is the type 

 of annulus formed on the scales of the Embiotocidse (see Fig. 4), 



(1913) 



FIG. 4. Lateral field of a scale from a three-year-old female of Amphigonop- 



tents aurora, showing the annul i. 



although an approximation of the circuli is also frequently evi- 

 dent, especially on the basal and lateral fields. 



That the annuli on the scales of Amphigonopterus aurora are 

 formed during the winter is evident from a consideration of the 

 following facts. A series of young from New Monterey col- 

 lected on October 26, and another lot from near Pillar Pt.. Cali- 

 fornia, obtained on November 25, show no trace of an annulus 

 at the margin of their scales, and had not yet attained the com- 

 puted length at which this mark had been formed in larger speci- 

 mens. Excluding recently born young, the smallest examples of 

 either sex among those taken near Piedras Blancas during the first 

 week of June, and also the young specimens secured near Pillar 

 Pt. on April I, have a single annulus on their scales, some dis- 



1 The statement by Taylor that no approximation of the circuli occurs in 

 the annuli is partially erroneous (particularly as it applies to salmonoid fishes), 

 as is also his conclusion that the annuli of the fishes which he studied were 

 formed during the summer (even Taylor's own data indicates the contrary). 



