BUNOTHERIA. 739 



the character of the tritubercular superior molar has recently impressed me 

 (see Proceedings of the Philadelphia Academy, 1883, p. 56), as it had pre- 

 viously done Prof Gill. This zoologist has already distinguished two divi- 

 sions of the Insectivora (without the Galeopithecidce), by the forms of the 

 superior molar teeth. The first possesses quadritubercular molars above, 

 the second tritubercular. That these tyj^es represent important stages in 

 the development of the molar dentition I have no doubt. These characters 

 far outweigh in importance those expressing the forms of the skull, matters 

 of proportion only, with which a few systematists unnecessarily overload 

 their diagnoses. Such characters are of little more than specific value, and 

 serve to obscure the mind of the inquirer for a true analj'sis. They may 

 be used emjDii'ically, it is true, to determine relationship when the diagnostic 

 parts are wanting. 



I proposed to transfer the Insectivora with tritubercular superior molars 

 to the Creodonta, in spite of the fact that some of them (^Mytliomys, Solenodon, 

 Chrysochloris) have but weakly developed canine teeth, and Chrysochloris has 

 large incisors. As an extreme form, Estlionyx will follow, standing next the 

 Tillodonta It will then be necessary to transfer the Arctocyonidse and all 

 the Mesodonta to the Insectivora, where they will find affinity with the 

 Tupceidce. These have well-developed canines and small incisors, as in the 

 extinct groups named. The Chiromyidce must be distinguished from all of 

 the other suborders, on account of its rodent-like incisors, combined with 

 its lemur-like feet. 



The characters of the five suborders will then be as follows: 

 I. lucisor teeth growing from persistent pulps: 

 Canines also growing from less persistent pulps, agreeing witb external incisors in 



having luolariform crowns .■ . i. Tceniodonta. 



Canines rudimental or wanting ; hallux not opposable ii. Tillodonta. 



Canines none ; hallux oppqsable Iii. Dauhentonioidea. 



II. lucisor teeth not growing from persistent pul^is : 



Superior true molars quadrituberculate ; hallux opposable iv. Prosimiw. 



Superior true molars quadrituberculate ; hallux not opposable v. Insectivora. 



Superior true molars trituberculate or bituberculate;' hallux not opposable. 



VI. Creodonta. 



'The internal tubercle is wanting in tlie last two superior molars in Hywnodon. This genus, of 

 which the osteology remains largely unknown, has been stated by Gervais to possess a brain of higher 

 t"pe than the Creodonta. Prof. Scott, of Priuceton, is, however, of the opinion that this determination 

 is erroneous, and that Hijwnudon is a true Creodont in this and other respects. If so, the genus wiU 

 perhaps enter the AmMyctonidce. 



