<>f tlie Pelvic Plexux in Acanthias vulgaris. 



13 



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. 



