42<) GRACE A. WELLS 



the rostrum the triangular process separating the anterior wall 

 of the brain case is visible in profile. 



In the lateral view no foramina are seen in the ethmoid region. 

 In the orbit they are numerous. Near the ventral side, at about 

 the middle of the orbit is the large optic foramen (II). In the 

 anterior part of the roof is that for the ophthalmicus superficialis 

 (o.s. VII) with behind it the seven or eight smaller foramina 

 for its branches to the lateral line organs on the top of the head. 

 Just in front of the postorbital process is the large trigemino- 

 facial foramen for branches of the fifth and seventh nerves 

 (t.f.), just in front of which is the oculomotor foramen (o?n. III). 

 About midway between the trigemino-facial and the main 

 ophthalmicus foramina, in the dorsal half of the orbit is the 

 small foramen for the trochlearis (IV). Antero ventral and 

 close to the trigemino-facial is the small opening for the abdu- 

 cens. Gegenbaur thought that the abducens left the cranium 

 together with the fifth and seventh nerves. This abducens 

 foramen is, however, mentioned by Allis ('14 b) and I find it as 

 described by him. 



Just beyond the abducens foramen is the transbasal canal 

 (tr.c.) while just antero-lateral to the main ophthalmicus open- 

 ing is the foramen for the passage of the ophthalmicus profundus 

 branch of the trigeminal. Below this last is the opening of the 

 so-called ethmoid canal, Reynold's orbito-nasal foramen (ex.). 

 Directly in front of the transbasal canal is a small opening for 

 the passage of a blood vessel which leaves the orbit through a 

 second foramen midway between the optic and the ophthal- 

 micus superficialis foramina. A minute canal perforates the 

 base of the postorbital process, opening on both anterior and 

 posterior surfaces, and associated with other small foramina in 

 the supraotic crest, for- the passage of posterior twigs of the 

 superficialis branch of the seventh nerve. 



A slight depression just in front of the foramen trigemino- 

 facialis marks the point of attachment of the optic pedicel 

 (o.p.). This is a cartilaginous stalk with a rotule at the distal 

 end for the support of the eyeball; it is not continuous with 

 the sklera of the eye, but is held within the connective tissue 

 which covers the ball. 



