THE SKULL OF ACANTHIAS VULGARIS 421 



superior canal (sx.) is practically a continuation of the former — 

 extending forward and outward, nearly parallel with the lateral 

 margin of the fossa endolymphaticus and gradually terminating 

 at about the line of the middle of the postorbital process. 



External to the postero-lateral angle and at the level of the 

 floor of the skull, is a notch in the cartilage (see figs. 1, and 7). 

 A cartilage bar continuous at either end with the margin of the 

 notch, converts it into a fenestra postotica (f.p.o.). This lies 

 behind and below the glossopharyngeal foramen (to be men- 

 tioned below) but the ninth nerve passes outwards and back- 

 wards above the fenestra. No nerve, blood vessel or muscle of 

 any size passes through it; but one of the dorsal longitudinal 

 muscles of the trunk has its origin from a fibrous fascia which is 

 attached to the postero-lateral angle of the cartilage bar and 

 the trapezius (T.) attaches to the outer angle. 



A number of foramina perforate the dorsal surface of the 

 cranium. Some of these are for the passage of nerves, others 

 for blood vessels. Just lateral to the rostrum, is a more or 

 less regular row of small foramina, which extends somewhat 

 diagonally (posteriorly and laterally) on the dorsal surface of 

 the nasal capsule. There are usually four — sometimes only 

 three — of these foramina, the one nearest the rostrum being the 

 largest. As nearly as could be determined after repeated dis- 

 sections of adult heads and injected garters, these are for minute 

 twigs of the ophthalmicus superficialis ramus of the seventh 

 nerve (o.s. VII). 



Numerous nerve foramina occur in the sulcus longitudinalis. 

 Posterior and slightly lateral to the above foramina are two 

 small foramina on either side — the inner for the passage of the 

 ophthalmicus profundus {o.pr.V.) branch of the fifth nerve and 

 the outer for fibers of superficialis. (Just anterior to the latter 

 a very small foramen sometimes occurs, for the passage of a mi- 

 nute twig of the ophthalmicus superficialis.) These were called 

 openings of the 'ethmoid canals' by Gegenbaur. Posterior to 

 these openings, on either side, is a large foramen for the main 

 trunk of the ophthalmicus superficialis branch of the seventh 

 nerve (o.s.) on its way to supply the ampullae of Lorenzini on 



