230 Part Ill.—Twenty-first Annual Report 
females determined. These were supplemented by similar particulars 
obtained by Mr. P. Jamieson at the Fish-market, and the collective 
results are here exhibited :— 
Females. Males. 
Species. | Total No. 
No. sp No. ei hs 
Grey Skate (2. batts), - - | 666 §1°3 631 48°7 1,287 
Shagreen Ray (R. fullonica), — - . | 4 50°0 4 50:0 8 
Thornback Ray (R. clavata).  - = 660 65°7 344 34:3 1,004 
Sandy Ray (R. circularis), - - 29 61:7 18 38°35 47 
Starry Ray (A. radiata), - - - 510 54°7 422 453 932 
It will be observed that in no case do the males exceed the females in 
number, and that with the exception of the shagreen ray, where the 
numbers are probably too small to indicate the real proportion, the 
females are in excess, The amount of the excess, however, varies. There 
is almost equality in the case of the common skate, while with the thorn- 
back, the starry ray, and the sandy ray—although here the figures are 
small—the excess of females is very considerable. ‘The measurements 
are scarcely sufficiently numerous to show the relative sizes of the sexes, 
but they suffice to indicate that the female is the larger. Thus the 
average breadth of forty-nine female starry rays was 26°2 cm., and the 
average breadth of thirty-one males 25'0cm. Thirteen female thornbacks 
had a mean width of 16°1 cm., and sixteen males a mean width of 14°2 
em. Six female common skates had a mean width of 41°4 cm., and six 
males 37°8. 
The measurements are not perhaps numerous enough to enable much 
to be said with regard to the rate of growth except iu the case of the 
starry ray. I give some of the measurements of the latter arranged in 
centimetre groups. 
| TABLE 
