I\IUSTELITS LJ'WIS. 141 



superior and tlie latter for the recti iiiternus and inferior. This 

 latter portion, which Herrick considers as the continuation of 

 the main nerve itself, runs forward dorsal to both the muscles 

 it innervates, and it is to it that the ciliary ganglion is said 

 to be related in Menidia, as I also find it in Scomber. 



Herrick says (32, p. 237) that the " deviations " in the inner- 

 vation of the internal and inferior recti in Menidia, from that 

 given by me in Amia, ''can be easily explained mechanically 

 by the great size of the eyes, and the consequent crowding 

 of the recti muscles far backward.^' Corning explains the 

 differences between Esox and the chick, the chick agreeing 

 practically with Amia, by assuming (p. 186) that the rectus 

 inferior of Esox acquires an origin dorsal to that branch of 

 the oculomotorius that innervates the rectus internus. He 

 does not say that the muscle traverses or is traversed by the 

 nerve in this process, but it is evident that one of these two 

 things must happen, for no simple shifting of the muscles at 

 their origins could derive one arrangement from the other. 

 This applies to Menidia as well as to Esox, and Herrick 

 doubtless recognised it, for although he would explain the 

 change in the relations of nerve and muscle by a different 

 principle, as explained below, he assumes that it could be 

 easily accounted for by a principle said to have been invoked 

 by me; his words being (p. 2o7) that "he (Allis) invokes a 

 principle to account for the diverse relations of nerve and 

 muscle in elasmobranchs, Avhich, if applied more broadly, 

 might weaken the phylogenetic value of some of his other 

 cases." This statement of Herrick's is, however, clearly 

 based on a misconception of the principle referred to as 

 invoked by me, which principle was contained in the state- 

 ment that the muscles I was discussing in elasmobranchs 

 "at their origins, either traverse or are traversed by the 

 issuing nerve." I expressly eliminated the probability 

 of a nerve cutting through a muscle or a muscle through 

 a nerve "midway in its length" (3, p. 522). 



This is, in fact, the vital point of the whole discussion. 

 Does a nerve ever cut through one of the eye-muscles " mid- 



