Herrick, Cranial Nerves of Amblystoma. 205 



and Siren lacertina [2], and in Siredon (Axolotl) mexicanus 

 [5 and 7.] 



The oculomotor nerve {pan.') innervates the usual four eyes 

 muscles. One branch passes directly to the m. rectus superior, 

 another to the m. rectus inferior. Another and larger branch 

 passes to the same muscle and then divides. One half passes 

 on the m. rectus internus and the m. obliquus inferior. The 

 other half for the most part remains within the m. rectus in- 

 ferior, though a few of the fibres pass forward beyond the mus- 

 cle and spread out on the ventro-mesal aspect of the bulb of the 

 eye. No trace of the ciliary ganglion was discovered. 



In Salamandra this nerve passes to the m. rectus superior, 

 m. rectus inferior, m. rectus internus, and m. retractor bulbi. 

 It also communicates with the trigeminus. 



The optic nerve {op.) does not exhibit a lumen, as in some 

 amphibians, though the axial portion is crowded with deeply 

 staining oval unipolar and bipolar nuclei. 



The olfactory nerve {ol.) does not separate into well-marked 

 dorsal and ventral branches, as in Salamandra, but breaks up 

 into a brush ol many small fibres. Terminal anastomoses with 

 the fifth were not observed. 



LITERATURE CITED. 



1. Arnold, G. A. The Anterior Cranial Nerves of Pipa Americana. Bulletin 



of the Essex Institute, XXV, 10-12, Dec, 1893; a ' so Tuft's College Studies, 

 No. 1, 1894. 



2. Ayers, H. A Contribution to the Morphology of the Vertebrate Ear, 



with a Reconsideration of its Functions. Journal of Morphology, VI, 

 1-2, May, 1892. 



3. Ecker, A. The Anatomy of the Frog. Translated by George Haslam. 



Oxford, 1889. 



4. Norris, H. W. Studies on the Development of the Ear of Amblystoma. 



Part I : Development of the Auditory vesicle. The Journal of Morphol- 

 ogy, VII, 1, 1892. 



5. Osborn, H. F. A Contribution to the Internal Structure of the Brain. 



Journal of Morphology, II, 1, July, 1888. 



6. v. Plessen, Jos. and Rabinovicz, J. Die Kopfnerven von Salamandra 



maculata im vorgeruckten Embryonalstadium untersucht. Munich, f. F. 

 Lehmann, 189 1. 



