No. 2.] ON- THE GUSTATORY ORGANS. l8l 



in number, are arranged in the form of an inverted V. Fungi- 

 form papillx are grouped quite thickly in the space bounded 

 by the circum vallate papillx, and are also scattered elsewhere 

 on the dorsum. The tip of the organ is obtuse, and the under 

 surface smooth and marked by a narrow groove extending from 

 the frcenum to the apex. 



In the young Liitra the dorsal surface, anterior to the cir- 

 cumvallate area, was thickly studded with fungiform papillae. 

 They were very evenly distributed, but were most thickly placed 

 along the median furrow, which in this tongue was well marked. 

 Far back on the dorsum were six or seven circumvallate papillae. 



GusTATORV Structures. 



The Circumvallate Papillce. — The papillae are 0.55 mm. in 

 diameter and 0.75 mm. in height. The trenches encircling 

 them are narrow and deep. Glands of the serous type are not 

 very abundant. The ducts open into the trenches at different 

 levels. The papillae of the young Litti-a were in better condition 

 for studying the arrangement of the bulbs than those of the adult 

 specimens. In the former the bulbs are disposed on the lateral 

 area in six to eight tiers. They are also present in the epithe- 

 lium of the outer wall, and even occur on the free upper surface 

 of the papillae. From horizontal sections there appear to be 

 about fifty bulbs in a tier. They measure 0.053 '^n^- ^^ length 

 and 0.030 mm. in breadth. 



The lateral gustatory organs appear to be rudimentary in 

 structure. They consist merely of a few simple folds of the 

 mucous membrane. The folds were destitute of bulbs, and no 

 glands of the serous type were detected in this region. 



The fungiform papillae contained bulbs as usual. One from 

 a papilla of the mid-dorsal region measured 0.045 ^ti"1- in length 

 and 0.027 mm. in breadth. The base of the bulb rested against 

 the mucosa, and the apex penetrated the superficial layers of 

 the epithelium. No bulbs were detected in the epiglottis. 



The Tongue of Cants lupus. 



This specimen and the following one were hardened in 

 Miiller's fluid and alcohol, according to the method already 

 described. 



