bail 
O. C. Marsh—The Order Theropoda. 337 
The Specimens of Zheropoda here first described, including 
the type specimen of Ceratosaurus na sicornis, are from the 
Atlantosaurus beds of the Upper J Aig in Colorado, where 
they were found by Mr. M. P. Felch. The asso sociated fossils 
are various Sawropoda, eee and Ornithopoda, together 
with Jurassic Mammal 
CLASSIFICATION. 
The main characters of the order Thero We ees aid of the 
families now known to belong to it, are as f 
Order THEROPODA. 
Large antorbital opening. Ver tebre more or less hollow. Fore 
limbs very small; limb bones ie Feet digitigrade ; digits 
With prehensile claws. Pubes projecting downward, with distal 
ends codssified. 
(1.) Family Megalosaurida. Anterior vertebrae convexo-concave ; 
remaining vertebre bi-concave. Pubes slender. Astragalus 
with ascending ioe ss. 
Gen (Poikilopleuron), Allosaurus, 
Oe siewas ge heruiols "Dryptosaurus (Leelaps). 
(2.) F amily Ceratosauride. haan on skull. Cervical vertebree 
pla ave, remaining vertebre bi-concave 
slender. Pelvic bones codssified. Osseous dermal plates. 
Astragalus with ascending process. 
Genus, Ceratosaurus. 
(3.) Family Labrosauride. Lower jaws edentulous in Ss 
Cervical and dorsal vertebr convexo-conca s 
slender, with nn margins united. aracalie with 
ascendin g proc 
Genus, poten: 
(4) Family Zanclodontide. Vertebrex bi-concave. Pubes broad 
elongate plates, with anterior ee united. Astragalus 
Without ascending process. Five digits in manus and pes. 
Genera, Zanclodon, cue 
* The ® presence of various genera of Dinosaurs closely allied to these A merican 
forms in essentially one eek igh in the Isle of Wight, su esosts | rs the pore in 
hich they occur are not Wealden, as generally supposed, Dut 
Am. Jour, Sor—Tare Series, VoL. XXVII, No. 160.— ie, tk 
