BRACHIOPODA. 319 



Genus AULOSTEGES, von Helmersen. 1847. 



PLATE XVn, FIGS. 47-49. 



1845. Orthis, db Verneuil. G6o1. Russ. d'Europe et des Mont. VOural, vol. ii, p. 198, pi. xi, fig'. 5. 



1847. Aulosteges, von Helmersen. Neues Jahrb. fiir Mineral., p. 330. 



1847. Aulosteges, von Helmersen. Bull. Acad. Imp. Sci. St. Petersboui-g, vol. vi, p. 135, pi. vi, fig'. 12. 

 1850. (?) Strophalosia, King. Monogi-. Permian Fossils England, p. 93. 



1853. Aulosteges, Davidson. Introd. British Fossil Brachiopoda, p. 116, pi. ix, figs. 212-216. 



1848. Aulosteges, Shumard. Trans. St. Louis Acad. Science, vol. i, p. 292, pi. xi, fig. 5. 



1861. Strophalosia, Geinitz. Dyas, Heft i, ji. 93. 



1862. Aulosteges, Davidson. Quarterly Journal Geological Society, vol. xviii, p. 33, pi. ii, fig. 7. 



1863. Aulosteges, db Koninck. Fossiles pa!6ozoiques de I'lnde, p. 41, pi. xii, fig. 7. 



1883. Aulosteges, Hall. Ann. Kept. N. Y. State Geologist for 1882, pi. (xvii) 48, figs. 47-49. 



1884. Aulosteges, Waagen. Palieontologia Indica ; Salt-Range Fo.ssils, vol. i, pt. iv, p. 661, pi. Ixii, 



figs. 1-4 ; pi. Ixiii, tig. 1. 



Diagnosis. Shell productiform in general aspect, somewhat depressed, not 

 attached. On the pedicle-valve the cardinal area is prominently developed, 

 frequently somewhat distorted; the delthyrium is closed by a convex deltidium 

 which is covered with little tubercles or spinules. Cardinal teeth rudimentary 

 or absent. In the brachial valve the cardinal area is linear, the cardinal process 

 large, quadrij&d ; its base being surrounded by a strong deltidial callosity. Bra- 

 chial ridges extending nearly to the anterior margin and abruptly incurving. 

 Otherwise the interior impressions are as in Productus. Surface of both valves 

 thickly set with spines. 



Type, Aulosteges variabilis, von Helmersen,= Orthis Wangenheimi, de Verneuil. 

 Permian of Russia. 



Observations. It was early observed by King that Aulosteges formed a 

 connecting link between Strophalosia and Productus. The constant presence 

 of the cardinal area and the usual absence of the hinge-teeth, show the correct- 

 ness of this observation as far as it bears upon the structure of these genera. 

 Aulosteges is chiefly if not wholly of Permian age, and it may perhaps be better 

 to regard it as a descendant or offshoot from Strophalosia ; showing the obso- 

 lescence of teeth, which is the tendency toward the prevailing brachiopod type 

 of that and the preceding fauna. The specific representation of Aulosteges 

 is quite meager. The original sjjecies, A. Wangenheimi, de Verneuil (which, 

 according to King, Davidson and others, is identical with, and therefore has 



