NATURAL SCIENCES OF PHILADELPHIA. 285 



Clamatores. Oscines. 



I. Tree-climbers, with long hiad toe and tail feathers stiffened and acute. 

 Dmdrocolaptidie. Certhiidx. 



II. Terrestrial in part, with the tertials as long as the primary quills. 

 Geobal/'die. Motacillidx. 



III. Tree-perchers with hooked bill, graduating from powerful to medium 

 and slender. 



Formicariidx. Turdidx. 



Thamnophilus. Bill strongest, hooked. Lanius. 



Formicarius. " moderate. Turdus. 



Formicivora. " weak. Sf/lvia. 



Rhamphocmmus. " slender (wrens). Troglodytes. 



IV. Flj-catchers with flat bill and weak legs ; wait for their prey and take 

 it on the wing. 



Tyrannidee. My,scicapa et aflF. 



V. Flat-billed berry and fruit eaters. 



Cotingidx. Bombycillidx. 



From the Mammalia the well-known series of the Marsupialia and Placen- 

 tialia may be chosen. 



Placentialia. Marsppialia. 



I. Toes unguiculate, in normal number ; sectorial teeth ; i. e., one or more 

 molars with one or no internal tubercles ; canines strong : 



Carnivora, Sarcophaga.* 



I. Digitigrade. 

 Toes 5—4. 

 b. Numerous sectorial tuberculars. 

 Tubercular molars 2.. 

 Canidffi. ^ * * 



Tubercular molars i (upper incisors more numer- 

 ous in some). 

 * * Thylacinida?. 



II. Plantigrade ; molars tubercular. 

 a. Posterior molars 4- 



Dasyuridae. 



* * 4 



aa. Posterior molars 2. 



Ursidfe. 



II. Toes unguiculate ; molars with more than one row of pointed tubercles; 

 canines weak or none ; incisors large. 



Insectivora. Entomophaga. 



a. True molars i, toes 4 — 5. 

 Tail naked. 

 Gymnura. Didelphys. 



Tail hairy. 

 Cladobates. Myoictis. 



IV. Molars with transverse crests, no canines ; tusk-like incisors ; pairs of 

 limbs of similar proportions. 



* Flower and Krefft show that the supposed carniverous Thylacoleo Ow. is allied to 

 Hypsiprymus, and probably similar in habits. 



1868.] 



