72 AMPHIBIA AND PISCES OF THE PERMIAN OF NORTH AMERICA 



ably the deeply cupped facet for the capitulum of a double-headed rib. 

 A sharp ridge on the sides of the vertebrae, just at the base of the neural 

 arch, is very similar to the same structure figured by Fritsch on the sides 

 of the vertebrae of Keraterpeton and Urycordylus from Bohemia, but an 

 examination of the specimens preserved in the museum at Prague did not 

 reveal this feature, probably because of the very poor preservation of the 

 specimens. 



Williston has figured the humerus of Crossotelos and gives the following 

 description: 



"It is a simple bone, moderately expanded at the extremities, with a 

 rather deep concavity longitudinally behind, and with but a small lateral 

 rugosity. All the specimens found show an incomplete chondral ossification. 

 The form was doubtless more or less aquatic." 



Williston also notes the presence of fine, abdominal ribs. 



B. EMBOLOMERUS Division. 



Family CRlCOTlD/e Cope. 



Am. Nat., vol. xviii, 1884, p. 38; Am. Nat., vol. xxviii, 1889, p. 861; Syllabus 

 of Lectures, 1898, p. 46. 



Original description: "In the family Cricotidse the chorda dorsalis is 

 persistent and large. The vertebral centra and intercentra are perforated 

 so as to resemble some kinds of discoidal beads. They form a characteristic 

 feature among the Permian fossils. The abdomen is protected by scales 

 arranged in chevrons. There is a parietal foramen, and the supratemporal 

 bone has a free external border like the squamosal of the crocodile." 



Revised description: 



1. Skull elongate, like Archegosaurus in form. 



2. Nares not terminal, near outer edge of skull. 



3. Orbits near middle of skull looking upward and outward. 



4. Intercentra complete perforated disks forming, with the simi- 



larly developed pleurocentra, embolomerous vertebrae. 



5. Two (?) sacral vertebrae, anterior one with a large rib. 



6. Caudal vertebrae numerous. Chevrons coossified with inter- 



centra. 



7. Ilium reptilian, with strong projection to the rear. 



8. A close abdominal armor of imbricate scales, arranged in a 



chevron pattern. 



Genus CRICOTUS Cope. 



Proc. Phil. Acad. Sc, 1875, p. 405; Proc. Am. Phil. Soc, vol. xxii, 1884, p. 28; 

 Am. Nat., vol. xviii, 1884, p. 39. 



Type: Some caudal vertebrae and other bones. Nos. 6517, 6519, 6520 

 University of Chicago. From near Danville, Illinois. 



Original description: "The caudal vertebra best preserved is stout, dis- 

 coidal in form, and deeper than wide. It resembles in form that of an her- 

 bivorous dinosaurian, but diff^ers otherwise. The articular faces are deeply 

 concave, the posterior most strongly so; and the middle is occupied by a 

 large foramen, whose diameter is about equal to that of the centrum on each 

 side of it. The lateral borders of the posterior articular face are expanded 

 backwards, and articulate with a bevel of the corresponding edge of the 



