OF THE TONGUES OF THE MAMMALIA. 505 



just visible to the naked eye. They have the usual arrangement, 

 and their distribution according to size takes the usual form. 

 Their characters are shown in text-fig. 42 D. 



They resemble the papillse of ^-1. grisescens in that those within 

 and behind the vallate area are not regularly arranged in oblique 

 chains. 



Lymiphoid Tissihe and Glands. — The base of the tongue is 

 delimited by a zone of prominent elevations, but no orifices of 

 glands are visible. These nodules have not been mentioned by 

 Tuckerman, who merely states that the base of the tongue is 

 wrinkled. He describes the mucous glands, which are arranged 

 in a small central and two lateral groups. 



The Lateral Organs (text-fig. 42 Ej. — The prominent lateral 

 organs form crescentic bodies on the sides of the tongue, the 

 concavities facing the lateral vallate papillaB, which are level with 

 the anterior laminae and sulci. The laminae and sulci are 

 numerous, and are irregula.r in position for they have been ac- 

 commodated within a small space. The right organ is "9 cm. long, 

 and has 9 laminte and 10 sulci. The left organ is 1 cm. long, 

 and has 10 laminae and 11 sidci. Many of the laminae have 

 secondary sulci, and some of the primary sulci are very wide. 



Tuckerman described the histology of the lateral organs. 



The Frenal Lamella (text-fig. 42 B). — The triangular lamella 

 forms a stout, thick plate with a notched apex and nodular sides. 

 Tuckerman described a lamella, with a fimbriated edge, which 

 possessed sensory (tactile?) end organs on its non-medullated 

 nerves, which form a network. Gegenbaur (11) criticises Tucker- 

 man's observations and thinks that the end organs are tactile in 

 function. 



The long, narrow, deep ventral mesial sulcus opens posteriorly 

 into a small deep, triangular fossa. It lodges a small, median, 

 triangular crest deiived from the short frenum. 



The Black-handed Spider Monkey {A. melanochir). 



Flower (3) describes the tongue as follows : — " The tongue is 

 rather lancet-shaped and pointed at the apex. The lateral group 

 of linear follicles at the base of the palato-glossal fold is very 

 distinct and large. The papillae generally are soft and small. 

 Of circumvallate papillfe there ai'e only two, situated side by side, 

 close to the middle line opposite the attachment of the palato- 

 glossal folds. The frenum is attached very near (three-tenths of 

 an inch) to the apex of the tongue, which has a stong median 

 groove below. The sublingual papilla is rather small, soft, thick 

 and pointed, with a slightly bifid apex." 



The Red- paced Spider Monkey (J.. pan^'scws). 



Mayer (4) described three vallate papillae forming a triangle. 

 Miinch (5) described the vallate papillaj of two specimens of 

 A. vellerosus. In one there were seven papillaj on each limb, but 



