CHAPTER X. 



ORDER CAUDATA DUMERIL, 1806. COAL MEASURES TO RECENT. 



Naked-skinned, elongate, tailed salamanders, mud-puppies, efts, newts, etc. 

 External plls present or absent in adult condition, but always present in young. 

 Limbs short, with usually 4 dibits on hand and 5 on foot, but this is subject to 

 much difference. Limbs never very stout. Carpus and tarsus cartilaginous. Skull 

 roof without the postparietal, postorbital, and supratcmporal. Skull elements 

 never ornamented and never cut by the lateral-line canals. Vertebras consisting 

 of a single element ; ribs short, attached to an elongate transverse process. Caudal 

 ribs seldom present. Parietal foramen lacking. No ventral armature. Fresh- 

 water inhabitants. 



Suborder PROTEIDA Cope, 1868. 



This order agrees generally with the Caudata, but presents one most important 

 feature of difference in the presence of the opisthotic. It is this point which gives 

 the Proteida its intermediate position between the extinct amphibians and the recent 

 species, and seems to indicate a connecting line from the Coal Measures down to 

 the present. The structure of the hyobranchial arches sustains this view. 



The hyoid apparatus differs from that of other adult Caudata and resembles 

 that of their larvae in having three epibranchials, instead of one only. The second 

 1>; i si branchial is also connected with the first, which is not the case with the other 

 Caudata. Three extinct genera are placed tentatively in this suborder. 



Family COCYTINIDjE Cope, 1875. 



COPE, Bull. U. S. Nat. Mus., No. i, p. 12, 1875. 



The present family, as here defined, includes the forms whose structure seems 

 to ally them with the modern salamanders. The character on which most depen- 

 dence is placed is that of the branchial apparatus, lacking in Hyphasma. The forms 

 are all incompletely known and the family will doubtless require revision on acqui- 

 sition of additional material. Three genera, each with a single species, are: 



Cocytiuns gvriiioidcs Cope. Linton, Ohio, Coal Measures. Based on the ventral impression of the 



skull, with the well-developed branchial apparatus. 

 Ericrpeton brancliialis Moodie. Mazon Creek, Illinois, shales. Based on impression of mandibles 



and branchial apparatus. 

 Hyphasma lavis Cope. Linton, Ohio, Coal Measures. Based on incomplete and obscure amphibian 



body, lacking limbs. 



Genus COCYTINUS Cope, 1871. 



COPE, Proc. Am. Phil. Soc., 1871, 177. 

 COPE, Geol. Surv. Ohio, n, pt. n, 360, 1875. 



Type: Cocytinus gyrinoides Cope. 



Vertebrae and ribs osseous; teeth on the premaxillary bone, none on the maxil- 

 lary; hyoid elements largely developed, an axialhyal with basihyal on each side, 

 closely united with the corresponding ceratohyal, at the end of which is an element 

 in the position of a stylohyal; haemal or basibranchials 3, the anterior 2, each sup- 

 porting i pleural branchihyal, and the third supporting one also, the first haemal 

 branchihyal on the inner side of the ceratohyal, approaching the median line, and 

 with elongate pleural element. 



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