1010.] The Tupaiidiv. 279 



Phyletic Interpretation of the more Important Characters of the Tupaiidce. 



Primitive M ar. s u pi o- Placental Characters. ? Arboreal habits and adap- 

 tations (p. 226); ? diet including insects and fruits; hairs on tail in 

 groups of three {Ptilocercus); p| not molariform ; upper molars tritubercular, 

 lower molars tuberculo-sectorial ; arrangement of the majority of the cranial 

 foramina except the optic and carotid foramina and the alisphenoid canal; 

 lachrymal foramen marginal or external; tympanic ring-shaped; seven 

 cervical vertebrae, parapophyses on lumbars, sacrum attached to pelvis by 

 one enlarged transverse process; vertebrae, ribs, sternum, scapula, clavicle, 

 pelvis and limb bones all normal; tail long, back arched; an entipicondylar 

 foramen; a third trochanter; pelvis with normal pubic symphysis; tibia 

 or fibula not united, borne on astragalus alone; manus and pes plantigrade, 

 digits V-V, claws compressed, poUex and hallux divergent; carpus normal, 

 with free centrale; tarsus normal. 



Special resemblances to Marsupials. Phalanger-like appearance of 

 Ptilocercus; scrotum in Tupaia remaining prepenial; slight palatal vacui- 

 ties (Tupaia); alisphenoid forming a small tympanic process; an ento- 

 tympanic, possibly derived from the tympanic process of the petrosal of 

 Marsupials (van Kampen); a venous posterior condylar foramen (Ptilo- 

 cercus). 



Primitive Placental Characters (cf. also, "Marsupio-Placental" characters 

 above). Dental formula derived by reduction from |^^^; m|; milk dentition 

 well developed (Weber, 1904, p. 370); p| not molariform; an alisphenoid 

 canal; optic well separated from foramen lacerum anterius (Ptilocercus 

 only). 



Insectivore characters. Insectivorous habits; elongate snout, elongate 

 premaxillaries; reduced canines; incipient diprotodonty; pi absent (a 

 frequent, but not invariable, Insectivore specialization); p|^ more or less 

 reduced; molars in Tupaia with sharp pointed cusps and enlarged styles; 

 resemblances to Ictops in the skull of the ancestral Tupaiid; foramen rotun- 

 dum confluent with for. lac. anterius (Ptilocercus); "sinus canal" and 

 supraorbital foramen prominent; stapes pierced by a bony stapedial canal; 

 digits II, III, IV subequal in both manus and pes, digit III being slightly 

 the longest; centrale carpi large; scaphoid uniting with lunar; uterus bi- 

 cornis. 



Lemuroid characters. Arboreal habits, ability to sit up and hold the food 

 between the hands; omnivorous modification of the molars (Ptilocercus) 

 brain and brain case large, cerebrum invading the frontal segment, face 

 bending down upon cranium; skull wide between orbits, a postorbital bar, 

 large orbits; supraorbital (Tupaia) and malar foramina; ectopterygoid 



