A Contriluitioii to the Aii.itoiny of Siroii Inocrtina. 675 



5. Terminal branches (Nervi op h th aim ici anteriores). 

 While within the nasal capsule, the main nerve resolves itself 

 into smaller branches, so that upon emergence from the anterior end 

 of the capsule it presents the appearance of a bundle of small nerves. 

 By th(i above description the complexity of the trigeminus ])ecomes 

 apparent, making it the more remarkable that Fischer, who for the 

 most part, gave such complete descriptions of the Urodelan nerves, 

 should content himself here with merely sayhig: „Es dürfte ül)erflüssig 

 sein, die P'ormen des Trigeminus bei Siren und Ämphiuma näher 

 zu beschreiben. Sie stimmen mit denen der eben abgehandelten Gat- 

 tungen so genau überein, class man die von ihnen gege- 

 benen Beschreibungen als für die ganze Gruppe der Perennibranchiaten 

 und Derotremen gültig betrachten kann" (.J. 132). 



III. Ramus maxillae s u p e r i o r i s. 



This nerve arises in common with Ilaraus ophthalmicus super- 

 licialis as the first of the three primary roots. The two pursue a 

 similar course as far as their emergence from beneath the muscles. 

 This takes place at the anterior borders of the temporalis and masseter 

 muscles, where the R. ophthalmicus superficialis is superior and the 

 R. maxillae superioris inferior. 



Immediately after its emergence, this latter nerve sends otf an 

 important branch, the N. com m uni can s m axilla ris. 



This branch passes downwards and inwards, finally uniting with 

 the N. communicans ophthalmicus to form N. nasal is internus. 



The main nerve there gives otf several cutaneous branches and 

 curves downwards and forwards, being distributed to the skin of the 

 upper lip. 



The farther fate of N. nasalis internus will be followed in the 

 section upon the nose. 



IV. Ramus maxillae inferior is. 



This is a mixed nerve, containing both sensory and motor fibres. 

 It originates as the central one of the main divisions of the ganglion, 

 crosses the R. ophthalmicus profundus ; thence passes gradually down- 

 ward through the fibres of the masseter, and finally reaches the man- 

 dible. When in this position, it has cast off all its muscular elements, 

 and now, as a purely sensory nerve, it runs along the mandible in 

 company with R. mandibularis facialis, as far as the symphysis. 



It gives oft" the following branches: 



1) While passing between temporalis and masseter , it sends 



