348 PEOF. T. W. BELDGE ON THE MOEPHOLGGY OP THE SKULL 



of the mandible, between the angular and splenial bones (PI. XXVIII. fig. 7, v.'"). 

 Humphry [13] has described a similar branch in Protopterus, and also states that it 

 perforates the lower jaw, but the statement is contradicted by Pinkus (I. c). Such a 

 nerve certainly exists in Lepidosiren and behaves as described above. 



The Facialis (vii.). — The superior palatine branch of this nerve leaves the Gasserian 

 recess by a very small foramen in its floor (PI. XXVIII. fig. 6, vii.'). After entering the 

 foramen the nerve pursues a forward course, perforating the trabecular cartilage, and 

 then runs between the cartilage and the palato-pterygoid and parasphenoid, near the 

 sutural line of the two bones ; eventually, the nerve emerges through a small aperture 

 in the angle between the antero-lateral margin of the parasphenoid and the inner 

 border of the palato-pterygoid (PI. XXVIII. fig. 3, vii.'), and is distributed to the oral 

 mucous membrane. One or two branches of the nerve can be traced forward, dorsad 

 to the palatine symphysis and directly beneath the upwardly-tilted basicranial cartilage, 

 and appear to supply the vertical folds of mucous membrane in the angles of the 

 palatine tooth-plates. 



The '• nervus lateralis facialis " (Pinkus, I. c.) leaves the Gasserian recess by the same 

 foramen which transmits the maxillary and mandibular divisions of the Trigeminus 

 (PI. XXVIII. fig. 6, v."). Soon after emerging from the " Schlafengrube " 

 (PL XXVIII. figs. 1 and 2, t.f.) the nerve divides into a ramus buccalis and a ramus 

 ophthalmicus superficialis, the latter accompanying one of the branches of the ramus 

 ophthalmicus profundus of the Trigeminus over the dorsal surface of the nasal capsule 

 to the skin of the snout. 



The ramus hyomandibularis traverses a relatively large foramen in the postero- 

 inferior wall of the Gasserian recess (PI. XXVIII. fig. 6, vii.). After perforating the 

 periotic capsule the foramen opens into the " Schlafengrube," and through it the 

 ramus hyomandibularis reaches the inner or under surface of the suspensorial cartilage 

 (PL XXVIII. figs. 3 and 4, PL XXIX. fig. 18, vii.), where it divides into opercular, 

 hyoidean, and external and internal mandibular branches. At the emarginate posterior 

 border of the suspensorial cartilage (fig. 3, vii.") the ramus mandibularis internus 

 passes forward between the cartilage internally and the contracted inferior portion of 

 the squamosal externally, and reappears on the outer surface of the suspensorium a 

 little above its articular condyle (PL XXVIII. figs. 1 and 2, vii."). At this point the 

 nerve is joined by a branch of the ramus mandibularis of the Trigeminus, and then 

 extends obliquely downward and forward to the outer surface of the lower jaw. The 

 corresponding nerve in Ceratodus (Van Wijhe, 40) and also in Protopterus (Humphry, 

 I. c, Pinkus, I. c.) behaves in an almost precisely similar fashion. 



The communicating branch between the Facialis and Vagus nerves emerges from the 

 Gasserian recess through the same foramen which also transmits the maxillary and 

 mandibular divisions of the fifth nerve and the nervus lateralis facialis (figs. 1 aud 2, 

 v."). In its course backward to join the great lateral branch of the Vagus, the ramus 



