41-i Wbrtman — Stitdies of Eocene Mammalia. 



no postglcnoid foramen ; presphenoid and basisphenoid early 

 coossified ; lachrymal confined within the orbit, having a quadrate 

 outline without vertical enlargement (except in Hylobates) ; ilium 

 expanded ; ischium with only moderate distal enlargement and 

 without strongly everted edges (except in Hylobates) ; head of 

 femur with well-developed neck and open digital fossa ; no third 

 trochanter ; no entepicondylar foramen ; hallux and metacarpal 

 of hallux as in Cercopithecidae ; pollex fully opposable ; sesa- 

 moids of flexor tendons of four outer digits in manus and pes 

 vestigial or wanting and keels absent (except in Hylobates) ; 

 foramina of atlas simple ; as in the preceding families, the mas- 

 toid process is rudimental or wanting and the premaxillo-maxil- 

 lary suture long persists, being obliterated Only in aged specimens ; 

 there is no foramen spinosum for the passage of the middle 

 meningeal artery, but a notch in the anterior external part of the 

 foramen ovale apparently represents it in the Gorilla and Chim- 

 panzee; the frontals meet in the middle line over the presphenoid 

 and behind the ethmoid (except in Orang). Simiidae. 



Premolars two above and below ; canines reduced and of no 

 greater vertical extent than premolars and incisors ; orbital and 

 temporal fossae distinct ; a spheno-parietal contact on the side 

 wall of cranium (variable) ; frontal and sphenoid not separated 

 by malar on side wall of skull ; molars fully quadritubercular 

 with superior trigonal ridges distinct ; first (third) inferior pre- 

 molar without any trace of elongate anterior border ; no petro- 

 tympanic bulla ; but a well-defined vaginal process and a 

 well-ossified and coossified stylohyal ; external auditory meatus 

 and carotid canal as in Simiidse ; no postglenoid foramen ; no 

 floccular fossa on inner surface of periotic ; presphenoid and 

 basisphenoid early coossified ; lachrymal confined within the 

 orbit, having a much greater vertical than antero-posterior dia- 

 meter ; distal enlargement of ischium reduced and edges not 

 everted ; neck of femur and digital fossa as in Simiidse ; hallux 

 enlarged, not opposable and in line with other digits ; keels, 

 grooves, and sesamoids of four outer metapodials of manus and 

 pes absent; foramina of the atlas simple; a well-developed mas- 

 toid process ; the maxillo-premaxillary suture early obliterated ; 

 a distinct foramen spinosum for the passage of the middle 

 meningeal artery; no union of frontals over presphenoid and 

 behind ethmoid. Hominidae. 



[To be continued.] 



