ORDER CAUDATA DUMERIL, 1806. 69 



dilated, fan-shaped distally, and supports two pleural elements. The muzzle pro- 

 jects over the lower jaw and was rather broadly truncate. The premaxillary teeth 

 are cylindric and 6 in number on each side. The maxillary bone is represented by a 

 lamina at each lateral extremity of the premaxillary. The mandibular rami are 

 very stout, as are also the ceratohyals. The vertebrae have possessed some apophy- 

 ses, apparently keel -shaped diapophyses. The ribs are slightly curved. 



MEASUREMENTS OF THE TYPE. 



mm. mm 



Length of specimen 32 Length of axialhyal 3 



Length of skull 12 Length of postbranchial 4 



Posterior width of skull II Width of vertebra r 



Length of premaxilla 5 Length of vertebra 3 



Length of mandible 10 Length of rib 6 



The other specimen of this species (fig. 160) is interesting in having 40 consecu- 

 tive vertebrae preserved, and 19 pairs of ribs attached in their natural relations to 

 the skull and hyal elements. There are a few hyal elements preserved, but nothing 

 is added to our previous knowledge. The ribs are quite as in the type specimen, as 



./ . - -u r- 







FlG. i6a. Nearly complete specimen of Cocytinus gyrinoides Cope, from the 

 Coal Measures of Linton, Ohio. Original in the American Museum of Nat- 

 ural History. X 0.95. 



are also the vertebras. The animal was apparently a slender, eel-shaped amphibian 

 comparing favorably with the modern Amphiuma in this respect. There are no 

 indications of limbs or limb girdles. 



MEASUREMENTS (No. 2564, AMERICAN MUSEUM OF NATURAL HISTORY). 



mm. 

 Length of entire specimen ......................................... 113 



Length of skull .................................................. 15 



Width of head posterior ........................................... 15.5 



Length of vertebra ............................................... 2 



Length of rib .................................................... 4 



Genus ERIERPETON Moodie. 

 MOODIE, Kans. Univ. Sci. Bull., vi, No. 2, p. 328, 1912. 



Type: Erierpeton branchialis Moodie. 



The generic characters are found, first of all, in the presence of hyobranchial 

 arches which indicate its relationship to the formerly described Cocytinus gyrinoides 

 Cope, from Ohio. The only other known extinct genera of Caudata which possess, 

 or at least have preserved, the hyobranchial arches are the Jurassic Hylcnobatrachus 

 from Belgium and Lysorophus from the Permian of Texas. The present form is widely 

 distinct from both of these genera in the shape of the mandible and the form and 

 arrangement of the hyobranchial bars. The genus Erierpeton finds its closest ally in 

 Cocytinus, in the family Cocytinidae, which possibly belongs in the order Caudata 

 and the suborder Proteida of Cope. 



