THE EYE-MUSCLE NERVES IN NECTURUS 



PAUL S. McKIBBEN 



The Anatomical Laboratory of the University of Chicago 



EIGHT FIGURES 



Information concerning the eye-muscle nerves in Amphibia 

 seems abundant. For SaUentia these nerves have been partially 

 described by Arnold ('94) and Strong ('95) and the relations in 

 the adult frog given by Gaupp ('99). In Urodela descriptions are 

 fragmentary for many species, but in Amblystoma, Herrick ('94) ; 

 Spelerpes, Bowers ('00); Amblystoma, Coghill ('02); Triton, 

 Coghill ('06) and Amphiuma, Norris ('08); the origin, course, 

 relations and distribution of these nerves have been quite fully 

 set forth. In Proteida, the classical description of Fischer ('64) 

 in Menobranchus (Necturus) is incomplete, as is that of Osborn 

 ('88), for Proteus, the extremely small size of the trochlear and 

 abducent nerves making them difficult even to identify. In his 

 study of the brain of Necturus, Kingsbury ('95) gives descriptions 

 of the origins of all the eye-muscle nerves. The present contri- 

 bution may serve to supplement the observations of Kingsbury 

 by adding descriptions of all the eye-muscle nerves in Necturus 

 from their origins to their distributions in the orbit. 



MATERIAL AND METHOD 



The specimens of Necturus maculosus Rafinesque used were 

 adult animals, varying in length from 36 cm. to 42 cm., supplied 

 by Alex Nielsen, Venice, Ohio. 



The extremely small size of the eye-muscle nerves makes them 

 difficult to study in fresh or preserved material; but by staining 

 with methylene blue, intra-vitam, and careful dissection under a 

 stereobinocular microscope, the origin, course and distribution of 

 each of these nerves may be quite easily demonstrated. 



153 



THE JOURNAL OF COMPARATIVE NEUROLOGY, VOL. 23, NO. 3 

 JUNE, 1913 



