418 Harris Hawthorne Wilder 



from tlie inner side of the two brain components in the normal place, 

 the first from the ventral side, at about the highest point in the bend 

 of the neural axis, the other from the dorsal side of this curve and a 

 little further back. From these points of origin they run parallel to each 

 other obliquely downward and forward, as shown in the profile view, 

 much as in the case of a perfectly normal embryo or as upon the outer 

 sides of the same components, where the corresponding nerves come down 

 to the two lateral eyes. At the level of section 180 the Trochlearis makes 

 a sudden bend and runs horizonally to its insertion into the superior 

 oblique muscle. The Motor oculi continues its straight course a little 

 farther and is eventually distributed to its usual muscles. 



The Sixth nerve, the Abducens, is peculiar at its source, although in 

 perfect accord with the conception of such a cosmobion as presented in 

 this paper. Since the separation of the two components is widest at 

 the anterior end of the body and becomes gradually less posteriorly, i. e., 

 more like a normal single individual, there must come a point, proceed- 

 ing from before backward, at which the cranial nerves of the inner sides 

 of the two components must be represented by apparently single, median 

 trunks, which are, nevertheless, potentially double. In this monster this 

 point is reached between the Fourth and Fifth nerves and while the inner 

 components of the former are separate and distinct, those of the latter 

 develop a single median Gasserian ganglion formed by the coalescence 

 of the two lateral roots. From this ganglion a strong branch passes 

 out to either component and runs across the back of the orbit between the 

 separate eye muscles. The relations of this nerve to the various muscles 

 and to the optic nerve identify it with the nasal branch of the Ophthalmic. 

 Behind this a much reduced pair of little branches undoubtedly repre- 

 sents the vestiges of the inner Maxillary nerves, the parts controlled by 

 which never develop. Since the Fifth nerve thus lies posterior to the 

 region that exhibits two separate trunks for its cranial nerves the Sixth 

 must be also median and apparently single. This is indeed the case, 

 and this nerve is found in contact with the posterior surface of the 

 Gasserian ganglion from which point it runs somewhat farther back 

 along the median line. When on a level with the external recti muscles 

 it makes a sharp turn to a horizontal position, and divides into two 

 lateral branches which supply the external recti and a part of the 

 retractores bulbi. 



While on the subject of cranial nerves it may be proper to add that, 

 although the components converge more and more posteriorly, there yet 



