210 The Microscope. 



admiring his fine brass work, and now and then trying their 

 skill by working his automatic microtomes. These excited a 

 good deal of interest, as did his new eye-piece micrometers. 



Herbert Spencer was there with some of his superb glasses; 

 good lenses in anybody's hands, but doubly so when Mr. Spencer 

 can manipulate them. Why is it he does the thing so easily and 

 in such a simple way ? 



Mr. E. Pennock represented Queen & Co., with a full line 

 of their goods. 



SELECTIONS. 



THE EPITHELIUM LINING THE MOUTH OF NECTU- 

 RUS AND MENOPOMA. 



SIMON H. GAGE, CORNELL UNIVERSITY. 



In frogs, as is well known, a lining of ciliated ephithelium 

 covers the free surface of the mucous membrane of the mouth 

 and oesophagus, and extends to or into the stomach. This is 

 true also of a great many other Amphibia, and the generalization 

 is made by Wiederscheim, (Lehrbuch der Vergleichenden Anat- 

 omie der Wirbel thiere, Band II., page 583) and by Hoffmann, 

 in the part Amphibia of Bronn's Klassen und Ordnung der 

 Thier-Reichs (p. 383), that a ciliated epithelium lines the mouth 

 and oesophagus of all Amphibia. (That is, frogs, toads and sal- 

 amanders of all kinds).* Hoffmann, citing Leydig as Author- 

 ity, makes but a single doubtful exception. In the exceptional 

 case the epithelium is said to be columnar and probably ciliated 

 with such fine cilia that they were not detected. Professor 

 Owen (Comparative Anatomy and Physiology of Vertebrates, 

 Vol. I., p. 435, 440) says that ciliated epithelium is present in 

 the mouth of most Amphibia and in the oesophagus of the triton, 

 and of the larvae (tad- poles) of frogs and toads.f 



* As the structural indications of a division into mouth and pharynx or 

 throat, in most Amphibia, are very obscure, if present, the alimentary canal pre- 

 ceding the stomach is, in this paper, considered to be divided simply into mouth 

 and oesophagus ; the beginning of the oesophagus being indicated by the narrowing 

 lumen and the beginning of the longitudinal folds. 



t The statement of Prof. Owen is very meager and neither makes a general- 

 ization nor admits of one. 



