Kingsbury, Brain of Nectunis. 165 



plexus, the lateral edges of the walls were approximated to a 

 greater or less degree. The same condition was observed by 

 Osborn ('88) in Proteus, and Mrs. Gage in Dicmyctyliis. At 

 this point the pia is much thicker and it is thought possible that 

 it may be due merely to a spreading of the parts caudad, pro- 

 ducing thus this appearance. 



EndolympJiatic sacs. — In Nectunis as in other Amphibia, 

 these come into close relations with the brain. The endolym- 

 phatic duct pierces the ear-capsule by a separate foramen and 

 expands into a simple sac which rests upon the metaplexus in 

 the immediate neighborhood of the seventh and eighth nerves. 

 Its diverticles are few and very small, attaining in no way the 

 extent and complexity found in the frog and by Mrs. Gage in 

 Diemyctyhis, where there is a communication of the two sacs 

 across the meson. Burckhardt has found the same relations of 

 the sacciis cndolymphaticiis in Protopteriis as in Amphibia : the 

 sacs are of great extent and divide into numerous diverticles, 

 but do not communicate across the meson. In the larval 

 Necturi examined the conditions were as in the adult, — the sacs 

 small and simple. In connection with the simple relations of 

 the saccus endolympJiaticus, it may be mentioned that no peri- 

 ganglionic glands were observed on either the Gasserian or 

 spinal ganglia, as in the frog. 



Myel. — This has received but slight attention from me, the 

 portion immediately adjoining the brain only being examined. 

 In form it is subcylindrical, differing in this somewhat from 

 Cryptobranchus and Siren (Kolliker, '93) in which it is more or 

 less flattened. No marked cervical enlargement was observed. 

 A dorsal furrow appeared to be wanting ; the ventral one is 

 well marked. A liganicntiim denticidatiim exists in the adult 

 Nectwus, where it forms a cord closely applied to the latero. 

 ventral aspect of the myel, which it leaves at intervals to pass 

 to the wall of the vertebral canal, apparently at the points of 

 articulation of the vertebrae ; the myel was not studied for 

 a sufficient distance, however, to warrant a positive statement as 

 to the relations of the ligament. 



The myel of Proteus has been studied by Klaussner ('84). 



