1894.] MICROSCOPICAL JOJJRNAL. 339 



a minute, the brush turned aside and tlie study of the 

 specimen continued. 



It has been found of the greatest convenience for dem- 

 onstrating preparations. The right thing can be found 

 in a very short time. For reference preparations for 

 students it lias also proved a great assistance. The 

 teacher can also feel confident that the student will find 

 and study the typical part of the preparation. 



The Histological Structure of the Enteron of N. Macuhitus. 



By B. F. KINGSBURY, 



ITHACA, N. Y. 



The large-gilled salamander of the lakes and rivers of 

 North America, Necturus maculatus, known to fishermen 

 as the "mud-puppy" or "water-dog," presents except- 

 ionally favorable opportunities for the study of the 

 structure and physiology of the digestive tract, surpass- 

 ing in many respects even the much-used frog. When it 

 is considered that the cells of the stomach epithelium of 

 Necturus are about three times as large as those of the 

 frog or cat, it may be recognized how clearly structure 

 and the changes accompanying functional activity can be 

 observed. 



The digestive tract in this animal is quite simple, and 

 consists of a mouth cavity, short, wide, esophagus, a long 

 tubular stomach and an intestine with two or three con- 

 volutions opening into a cloaca. A distinction between 

 a small and large intestine such as occurs in the majority 

 of Amphibia is wanting. 



The mouth is lined with a stratified epithelium, which 

 is non-ciliated, a condition the reverse of that found in 

 the majority of Amphibia investigated. As far as can 

 be judged, those Amphibia in which cilia are wanting in 

 the mouth are those whose entire life is spent in the 

 water. The epithelium cells here resemble very much 

 those of the epidermis. No salivary glands, or glands 



