941 



Nachdruck verboten. 

 On the Gustatory Organs of Piitorius yison. 



By Fkedeeick Tückekman, Amherst, Mass., U. S. A. 



It will be of interest first to describe briefly the form and general 

 appearance of the tongue of this little animal. 



The organ measures 37 mm in length, 12 mm in breadth, and 

 8 mm in thickness, and is perfectly free for 13 mm from the fraenum. 

 The upper surface is marked by a longitudinal medial groove or fur- 

 row extending from the base to the tip. In the middle third of its 

 course this furrow is quite deep and is clearly defined, but as it nears 

 the base and anterior extremity of the tongue it becomes superficial 

 and finally disappears. The dorsum, anterior to the area of the pa- 

 pillae circumvallatae, is covered with small, glistening, recurved pa- 

 pillae of mechanical function, which are disposed in subparallel rows 

 running somewhat obliquely from the median furrow to the lateral 

 margins. This symmetry of arrangement ceases a short distance from 

 the tip of the organ. These papillae vary a little in form, and those 

 nearest the lateral contours of the tongue are smaller than elsewhere. 

 They measure about 0,30 mm in height and 0,20 to 0,25 mm in 

 breadth, and are about 0,05 mm apart. They are more or less flat- 

 tened on top, with perpendicular sides, and each one is seated upon 

 one or two papillary upgrowths of the mucosa. These papillae usu- 

 ally have a single, rather coarse, darkly-pigmented, horny spinule pro- 

 jecting from the inner angle of their upper surface, the point of which 

 is directed inwards and backwards. 



Fungiform papillae are thinly scattered over the dorsal surface, 

 being most conspicuous in the space bounded by the circumvallate 

 papillae. Taste bulbs are present at the upper part of many of these 

 papillae, particularly those of the middle and posterior regions of the 

 tongue. They are situated partly in the mucosa and partly in the 

 epithelium, their apices failing, in many instances, to perforate the 

 outer layers of the epithelium. They vary greatly in size. One of 

 the largest that I measured was 0,040 mm in length and 0,021 mm 

 in breadth. 



The extreme posterior dorsal surface is somewhat wrinkled, and 

 is devoid of papillae. The under surface of the tongue is thrown into 



