Q2 TUCKERMAN. [Vol. VII. 



papillae, three in number, are arranged in an isosceles triangle, 

 the apex of the triangle being directed backwards. The lateral 

 gustatory organs appear to lie normally. The fraenal process, 

 or sublingual plate, was lacking. 



GUSTATORY STRUCTURES. 



The Circumvallate Papillce. — The summits of the papillae 

 are smooth and flattened, and their sides are vertical. They 

 measure 1.05 mm. transversely, and are 0.90 mm. in height. 

 Serous glands are not abundant. The bulbs are disposed in 

 some ten tiers, with ninety closely packed bulbs in a tier. 

 They measure 0.05 1 mm. in length and 0.030 mm. in breadth. 



The Lateral Gustatory Orgatis. — The organs measure 12 mm. 

 in length and 2.5 mm. in breadth. The folds, eight or nine in 

 number, are flattened on top, and the furrows average in depth 

 0.90 mm. Serous glands occur within the folds, but are not 

 plentiful. Bulbs are here and there present on the upper surface 

 of the folds, and their lateral walls usually contain many tiers. 

 Their dimensions are the same as those given for the circumval- 

 late papillae. 



The fungiform papillae bear bulbs as usual, and they also 

 occur at the lower part of the posterior surface of the epiglottis. 



The Tongue of Ateles atcr. 



General Description. — The organ measures 54 mm. in length, 

 20 mm. in breadth, and is free from the fraenum for 12 mm. 

 It is quite thick posteriorly, and the general surface is smooth 

 and yielding to the touch. The under surface of the free por- 

 tion is impressed by a deep wedge-shaped groove extending from 

 the fraenum to the tip. The fungiform papillae are abundant 

 only at the tip ; beneath it, they are large and closely packed. 

 As in Lermir inongoz, the circumvallate papillae consist of two 

 pairs. The posterior pair are 2.6 mm. apart, and 13 mm. from 

 the base of the tongue. The anterior pair are well forward, 

 being 10 mm. from the posterior pair and 1 1 mm. apart. The 

 two pairs of papillae, seen from above with a low power, show a 

 marked difference in external characters. The summits of the 

 posterior pair are smooth and circular. The anterior pair, on 



