56 



REVISION OF THE PELYCOSAURIA. 



Revised description : 



(i) Spines as in D. macrospondylus, but with very prominent and slender fore 

 and aft ridges at the base. 



(2) Third to sixth cervicals with axis through neural arch and middle of cen- 



trum vertical. 



(3) Intercentrum of mid-dorsal and lumbar regions small and without promi- 



nent tenninal facets. 



(4) Lumbars with keel on mid-line of centrum below. 



(5) Size, small, i to 1.3 meters. 



Dimetrodon navajovlcus sp. nov. 



Type: A w-ell-preserved humerus in a large number of bones belonging to dififer- 



ent individuals under the general No. 2298 Am. Mus. Nat. Hist., Cope, coll., from 



which are selected certain humeri, femora, and vertebra for description. From El 



Cabre, New Mexico. 



Description : 



(i) Spines unknown. 



(2) Cervicals unknown. 



(3) Intercentrum unknown. 



(4) Character not shown. 



(5) Size, small, i to 1.3 meters. 



(6) Humerus with entepicoudj-le 

 proportionately ver>' much longer than 



po \ ^ ^^ \^ I in any other species of the genus. The 



radial crest is separated from the proxi- 

 mal end by a considerable space. 



Pig, 15.— Outline o( ihe lower jaw of D. longiramus. No. 4091 Am. Mus. X Vi- 



Fig. 16.— Outline o( the scapula of the same, st/, scapula. <o, coracoid. /(, procotacoid. X Vi- 



There is in the Cope collection a considerable quantity of material from 

 New Mexico, El Cabre and Arroyo de Agua, names that do not appear on 

 the maps. Among these, two Pelycosaurians are distinguishable, D. nava- 

 jovicus and Elcabrosaurns baldzvini. 



The specimens consist of fragments only, and each lot generally con- 

 tains the remains of several individuals. They were preserved by Cope in 

 small boxes and on the cover of one. No. 2299 American Museum, contain- 

 ing a characteristic humerus is written the name "navajovicus." I shall 

 adopt this name for the species, but another lot, No. 2298 American Mus- 

 eum, seemingly one individual, and containing fragments from other parts 

 of the skeleton and in better state of preservation, is described as the type. 



