48 CARBONIFEROUS AMMONOIDS OF AMERICA. 



Since that time species of this genus have been found in the Permian 

 of India, Sicily, and Texas, and one species has recently been described 

 by Diener" from the Lower Trias, so that it is no longer to be regarded as 

 exclusively Paleozoic. 



As to the systematic position of this genus there is no doubt, for 

 Karpinsky'' settled that question by his researches in the ontogeny of 

 Medlicottia, Fronorites, and kindred forms. The only question now is 

 whether MedJkottia is to be ^^laced in a separate subfamily, Medlicottin*, 

 or whether the larger group, ProlecanitidsE, shall be retained. Waagen 

 regards the latter grouj) as a suborder. 



Medlicottia coi>ei White. 



PI. XXII, figs. 1-8. 



1889. MeiUcottia copei, C. A. White, Am. Nat., Vol. XXIII, p. 117, PI. I, figs. 1, 3. 

 1891. MedUcottia copel, C. A. White, Bull. U. S. Geol. Survey No. 77. p. 21, PL I, 



figs. 1, 3. 

 1901. Medlicottia copei, F. Frecli, Die Dyas, p. 512, figs. 1 unci 2. 



Shell discoidal, compressed laterally, sides almost flat, narrow umbilicus; 

 narrow flattened venter, with moderately deep ventral furrow bounded by 

 angular and slightly beaded keels. Whorls involute and deeply embracing, 

 becoming more so as age advances. Surface almost smooth, ornamented 

 with fine curving cross ribs; the spiral ribs or striae that are found on some 

 species of MedUcotiia have not been observed on the Texas specimens. 

 The septa are complex, as is always the case with this genus. The siphonal 

 lobe is long and narrow, with a number of small denticulations on the 

 sides. The external saddle is deeply digitate and rather broad. The 

 lateral saddles are long and tongue-shaped, but entire. The four principal 

 lateral lobes are narrow and deeply l)ilid. There are also about eight 

 auxiliary lateral lobes, of which the two highest upon the sides are bifid, 

 and those nearer the umbilicus undivided, thus exemplifying Jackson's 

 law of localized stages of development. 



Occurreyice. — In the Permian of Baylor County, Tex., at the military 

 crossing on the Big Wichita River; also near San Angelo, Tom Green 

 County, Tex. 



«Pal. Indica, Ser. XV, Himalayan fossils, Vol. II, Pt. I, p. 58. 

 ^Ammoneen iler .\rtinsk-Stiife. 



