CHAPTER XVIll. 



THE MICROSAURIAN FAMILY NYRANIID^E, FROM THE COAL MEASURES OF OHIO. 



Family NYRANIID^ Lydekker, 1890. 

 LvDEKKER, Cat. Fossil Reptilia and Amphibia, p. 166, 1890. 



Skull with the palatines situated near the middle Une, internally to the 

 vomers and pterygoids, and the palatine vacuities small and placed far back. 

 Vertebrae (Ichthyerpeton) discoidal. Teeth less complex than in the Anthraco- 

 sauridae. A ventral armor present and the entire body covered with small cycloid 

 imbriated scales. 



The type genus of this family was placed by Fritsch (251) with the Archegosau- 

 ridae, although its resemblance to Anthracosaiirus was pointed out; it was subse- 

 quently made the type of a family by Lydekker (393) in 1890, and placed next the 

 Archegosaiu-idae. Known from the Coal Measures of Bohemia, Ireland, and Ohio. 



Two genera from North America, Ichthyerpeton and Cercariomorphis, are 

 assigned tentatively to this family, both known from the Coal Measures (462) of 

 Linton, Ohio, and both with the body completely scaled. The distinguishing char- 

 acters are found chiefly in the shape and arrangement of the scales, the structure, 

 form, and size of the body, all of which are given full treatment in the discussion 

 below. 



Genus ICHTHYERPETON Huxley, 1866. 



Huxley, Trans. Roy. Irish Acad., x.\iv, p. 195, pi. xxiii, fig. i; Scientific Memoirs, in, p. 195, pi. 23, fig. i, 

 1866. 



The genus was founded by Huxley (334) for the reception of the species Ichthy- 

 erpeton bradleycB from the Kilkenny Coal Measures of Ireland. The remains of the 

 type specimen represent "the hinder moiety of the trunk, with the greater part of 

 the tail, of an animal whose scaly integument and laterally compressed, fin-like tail 

 might easily lead one to take it for a fish, were not its true position among higher ver- 

 tebrata settled at once by the digitate hind limb ; while its alliance with the labyrin- 

 thodonts is indicated by the delicate spicular ossicles, which form a rudimentary 

 dermal shield along the belly." (Huxley.) 



Ichthyerpeton squamosiun Moodie. 



MooDlE, Jour. Geol., xvii, No. i, p. 69, 1909. 

 Moodie, Proc. U. S. Nat. Mus., 37, p. 24, 1909. 



Type : Specimens Nos. 4476 and 4459, U. S. National Museum. 



Locality and horizon : Linton, Ohio, Coal Measures. 



The present species is based on well-preserved remains from the Linton, Ohio, 

 beds. There are two specimens of the species preserved on blocks of coal and 

 together they represent the greater part of the length of the animal. The species is 

 located in the genus Ichthyerpeton, which was founded by Huxley (334, p. 351) on 

 remains from the Coal Measures of Ireland, on accotmt of the character of the der- 



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