Bekde.] Carboniferous Invertebrates. 81 



of the flattened area, and fades out. Adductor scars moderately 

 small, elliptical in outline, placed longitudinally and close to the 

 median ridge, a little anterior to the lateral ridges. Brachial 

 markings not prominent and generally indistinct, extending 

 outward from the anterior end of the adductor scars, curving 

 forward and ending near the anterolateral portion of the 

 flattened area. Other internal markings unknown. Length, 

 20 mm. ; width, 35 mm. ; convexity, 33 mm. 



Range and distribution : Upper Coal Measures ; Kansas 

 City, Turner, Wyandotte county, Lawrence, Topeka, Wabaun- 

 see county. Common throughout the Coal Measures and 

 lower portion of the Permian. 



This species differs from the previous in being smaller, hav- 

 ing a more distinct mesial sinus, ears separated from the body 

 of the shell by a ridge which generally bears spines and un- 

 equal costa^ on the anterior slope. 



The markings of this shell vary considerably in different in- 

 dividuals. They are not so distinct as those of a Russian ex- 

 ample in the collection, and the shell is smaller; though the 

 ridge separating the ear from the shell is present and spinous, 

 it is not nearly so pronounced as in the Russian specimen. 



Productus longispinus? Plate IX, fisrs. 9-9d. 



Productus longispinus Sowerby ? Min. Con., i, p. 154, pi. lxviii, f. 1, 



(1814). 

 Productus longispinus Salter, Quart. Jour. Geol. Soc. Lond., xvn, p. 64, 



pi. iv, f. 2, (1861); Meek, Fin. Rep. U. S. Geol. Surv. Neb., p. 101, pi. 



vi. f. 7, pi. vin. f. 6, (1872); etc. 

 Prod actus flemmingi Roemer (non deKoninck), Kreidebildung Texas, 



p. 89, pi. xi, f. 8, (1852): etc. 

 Productus splendent Norwood and Pratten, Jour. Acad. Nat. Sci. Phil., 



in, p. 11, pi. i, f. 5, (1854); etc. 

 Productus wabasken&is Norwood and Pratten, ibid. 

 Productus orbignyanus Geinitz ( ?non de Koninck |,Carb. u. Dvasin Neb., 



p. 56, pi. iv, ff. 8-11, (1866). 

 ProduHus horHdus Geinitz, ibid., f. 7. 



Meek's description (in part): " Shell small, thin, wider than 

 long ; hinge line generally longer than the transverse diameter 

 of the valves at any point farther forward, and terminating in 

 more or less distinct, rather vaulted, and often refiexed ears; 

 anterior and anterior-lateral outlines approaching a semicircu- 



