248 PROCEEDINGS OF THE ACADEMY OF [April, 



Each of these broad comb-like teeth is implanted by a single conical 

 fang excavated by a pulp cavity which divides into as many 

 canals as there are divisions of the crown, each canal passing up 

 the latter to its extremity. What particular purpose these comblike 

 incisors subserve in Galeopithecus is difficult even to imagine. It 

 is very unlikely that, as has been suggested, the animal uses them 

 to clean its skin. It is far more probable that Ihe peculiar form of 

 these teeth depend in some way upon the nature of the food, which 

 consists of leaves, remains of the latter being found between the 

 teeth, on the tongue and in the oesophagus, and that they have been 

 gradually developed from the tooth of some ancestor in which a 

 slight furrowing of the crown existed and which, being of advan- 

 tage, was gradually intensified in its posterity. In support of 

 such a view it may be mentioned that there is a slight indication of 

 furrowing of the crown in the incisors of the lower jaw in Hyrax, 

 Indri, Tupaia, Bhyncocyon, Desmodus and Diphylla among Chirop- 

 tera. Another interesting peculiarity in regard to the dentition of 

 Galeopithecus is the fact of the outer incisor of the upper jaw 

 having two roots, which is also the case not unfrequently in Petro- 

 dromus and in certain species of Erinaceus. The canine of the 

 upper jaw in Galeopithecus are likewise provided with two roots, as 

 was the case in the extinct Jurassic mammals, Pantotheria,^* another 

 illustration of the affiliation of Galeopithecus with extinct mamma- 

 lian forms. 



The tongue is dented at the end, the dents supporting roimd 

 papillse. This pectinated condition of 'the end of the tongue may 

 possibly be correlated in some way with that of the lower incisor 

 teeth. The under surface of the tongue is deeply grooved. Two 

 large circum vail ate papellse and foliate papillae at the sides of the 

 tongue are also present. There is only a slight indication of the 

 under tongue, so prominent a feature in lemurs, which is present 

 also in Tiqyaia, but entirely absent in Chiroptera. 



The stomach (Plate XII) is very much elongated and drawn 

 out, resembling that of Pteropus. The mucous membrane of the 

 cardiac part is smooth. That of the pyloric part lying toward the 

 cardia is thrown into deep folds, which run parallel with the long 

 axis of the stomach, while the remaining part of the pyloric mucous 

 membrane is smooth again. The small intestine preserves about the 



" Marsh, Amer. Journal Arts and Sciences, Vol. 20, p. 239, 1880. 



