Page:Proceedings of the Royal Society of London Vol 69.djvu/21

Rh and the number of nerves innervating the fin a correlation which on the side-fold excalation hypothesis we might be led to expect I counted the fin rays in a dozen specimens of females. A small + after the number of fin rays denotes that it was uncertain whether an additional propterygial ray existed or not, the element in question being exceedingly small.

The result of the examination is given below :

Number of

specimen in

Table I.

oo 63 61 52

71 89 51 56 80 81 95

Table V.

Number of fin rays.

16

16 16

16 + 17 17

17 + 18 18 18 18 19

Number of nerves to fin.

19 18 20 18 19 19 20 18 18 18 18 19

A glance at the above table will show that there exists apparently no correlation between the number of fin rays and the number of nerves to the fin. Perhaps, however, it is best not to lay too much stress on this evidence, as the number of specimens examined is not very large.

VII. Variations in the Number of whole Vertebra'.

Mention has already been made of the way in which the point of junction between the half and the whole vertebrae was determined. The subjoined table gives the number of the whole vertebrse in the . h'f ty specimens of each sex.

Table VI.

Number of whole

vertebrae.

45

3

2

Average for $ 46 '98

46

14

14

? 47 -28

47

18

15

48

13

10

Diff 00-30

49

5

50

1

4