132 EDWARD PHELPS ALFilS, JUN. 



lire g-iven off, and, ninniug forward and upward, join the 

 ramus oplifchalmicus profundus anterior to the point where a 

 first large branch arises from that nerve. They accordingly 

 represent the radix longa, and their point of origin from the 

 profundus would seem to indicate that they cannot be 

 sympathetic nerves, unless they have an intra-cranial sym- 

 pathetic origin. No extra-cranial sympathetic strand going 

 to the ganglion could be recognised, but it is here too diffi- 

 cult to recognise small nerve strands for me to assert that 

 none existed. The radix brevis is represented by fibres that 

 bind the ciliary ganglion and ocnlomotorius together. 



The two nerves that together represent the radix longa lie, 

 in their forward and upward course, posterior to the nervus 

 opticus, anterior to the i-ectus inferior, and ventral to the 

 rectus internus. Just before they join the profundus a 

 line of tissue runs from them toward the optic nerve. 

 Whether this line of tissue is wholly fibrous or partly 

 nervous I could not determine, and it will be further re- 

 ferred to in describing the ramus ophthalmicus profundus. 



Anterior to the ciliary ganglion the oculomotorious con- 

 tinues forward to the obliquus inferior, here having its 

 well-known relations to the other structures in the orbit. 



Nervus Trochlearis. 

 The nervus trochlearis issues from the skull as two branches, 

 as Tiesing found it, its foramen lying directly internal to the 

 ramus ophthalmicus superficialis. The nerve runs forward 

 and downward around the lower edge of the ophthalmicus 

 superficialis, here being closely pressed against that nerve, 

 but, contrary to Schwalbe's statement (57, p. 186), without 

 any apparent interchange of fibres. Lying ahvays dorsal to 

 all the other structures in the orbit, it goes to the obliquus 

 superior muscle which it, and it alone, innervates. 



Nervus Abducens. 

 The nervus abducens issues through the large trigemino- 

 facial foramen, lying along the ventral surface of the tri- 



