1877.) 61 
[Cope. 
Fam. PycnNopoNTIDz, 
Teeth obtuse molar, covering the vomer and palatine bones; no basilar 
interneural and interhemal bones; chevron-shaped bones protecting the 
dorsal region, their branches extending on the sides ; abdomen protected by 
similar bones, which form plates on the median line ; interneurals continued 
far forwards.—Microdon, Pycnodus, Gyrodus, Mesodon. 
Order DocorTERI mihi. 
Scapular arch suspended to the cranium ; pectoral fin with numerous, 
(not more than fifteen known) basal radii; ventral fins thoracic. Dorsal 
and anal fins with basilar interneurals. 
Fam. DORYPTERIDA. 
Vertebral column osseous ; caudal fin not or very shortly vertebrated. 
Interneural spines corresponding with the basilars on the abdominal, but 
not on the caudal parts of the vertebral column. Ribs complex, united with 
abdominal dermal bones which form a series of median plates. 
None of the Isospondylous families above described possess the dental] 
characters of the Saurodontidea, i. e. the long fangs set in deep alveoli. 
RHYNCHOCEPHALIA. 
CLEPSYDROPS COLLETTII Cope, Proceedings Academy, Philadelphia, 1876, 
p. 407. 
This species proves to be the most abundant land vertebrate of the 
formation. It is represented in all the collections, sometimes by portions 
of individuals of double the size of the types. I referred this genus 
to the Rhynchocephalia originally, although it possesses a few batrachian 
characters. The occipital condyles preserved in the present collection are 
simple and median, thus confirming the reference, were confirmation 
needed. A supposed sacral vertebra is free at both extremities, and 
presents on each side, just behind the articular extremity, a very large 
facet, extending from a rudimental diapophysis to the plane of the inferior 
surface of the centrum. The specific reference of this vertebra is not 
certain. 
CLEPSYDROPS VINSLOVII Cope, sp. nov. 
This species is represented by a third cervical vertebra ; and probably 
by other centra, but in this one the characters distinguishing it from C. 
collettdt are especially visible. 
The inferior median line is a keel, some distance above it, the sides of 
the centrum are full, rising in a longitudinal angle. There is no constric- 
tion or fossa below the diapophysis as in C. collett¢/, The latter is anterior 
in position, is vertically compressed, and is curved forward for a short dis- 
tance below. The posterior articular face is regularly funnel-shaped from 
the margin ; the anterior face hasa broad recurved lip. This passes round 
the inferior margin, which is not projected forwards as in C. colletti’. The 
