162 PAUL S. McKIBBIN 



probably, only vaso-motor fibers. In Squalus acanthias, accord- 

 ing to Senior, physiological examination reveals great simplicity 

 of accommodation; a fact correlated with the absence of the 

 ciliary ganglion. No similar experiments with Necturus are 

 known to the writer. 



SUMMARY 



In Necturus all the eye-muscle nerves have been demonstrated 

 from their origin to their distribution in the orbit. 



The trochlear nerve shows frequent variations in its intra- 

 cranial course and in the position of its foramen in the parietal 

 bone. 



No group of cells corresponding to the ciliary ganglion has 

 been found, but there are quite constantly present twigs from 

 the r. ophthalmicus profundus V, the oculomotor and the abdu- 

 cent nerves which enter the bulbar fascia and the eyeball. These 

 twigs most often appl}^ themselves to the sheath of the optic 



nerve. 



LITERATURE EXAMINED 



Arnold, G. A. 1894 The anterior cranial nerves of Pipa americana. Tufts 



College Studies, March. 

 Bowers, Mary A. 1900 The peripheral distribution of the cranial nerves of 



Spelerpes bilineatus. Proc. Amer. Acad. Arts and Sci., vol. 33. 

 CoGHiLL, G. E. 1902 The cranial nerves of Amblystoma tigrinum. Jour. Comp. 



Neur., vol. 12. 



1906 The cranial nerves of Triton taeniatus. Jour. Comp. Neur., vol. 

 16. 



DoDDS, G. S. 1906 The cranial nerves of one of the salamanders (Plethodon 

 glutinosus). Univ. of Colorado Studies, vol. 3. 



1907 On the brain of one of the salamanders (Plethodon glutinosus). 

 Univ. of Colorado Studies, vol. 4. 



Drtjner, L. 1900 Uber Mikrostereoskopie und eine neue vergrossernde Stereo- 

 oskopcamera. Zeitschr. f. wissensch. Mikroskopie u. f. mikrosk. 

 Technik, Bd. 17. 



Fischer, J. C. 1864 Anatomische Abhandlungen uber die Perennibranchiaten 

 und Derotremen. Hamburg. 



Fish, Pierre A. 1895 The central nervous system of Desmognathus fusca. 

 Jour. Morph., vol. 10. 



Gage, Susanna Phelps. 1893 The brain of Diemyctylus viridescens, from lar- 

 val to adult life and comparisons with the brain of Amia and Petro- 

 myzon. Wilder Quarter Century Book. 



