FOSSILS OF THE DEVONIAN. 



195 



Genus SCOLIOSTOMA Braun. 



Scoliostoma Americana, n. sp. 

 Plate vi, figs. 1, 1 a-e. 



Shell small, cylindro-conical exclusive of the expanded inner lip of the 

 aperture; apex obtuse; whorls five, slightly convex Aperture contracted 

 and turned obliquely outward and backward at right angles to the outer 

 surface of the last whorl; outer lip somewhat thickened and rounded; inner 

 lip expanded, extending up on to the whorls and directed outward; a swell- 

 ing occurs opposite the outer lip that occupies its lower central portion; 

 margin of inner lip very thin. Umbilicus concealed. Shell rather thick. 



Surface of shell marked by a few concentric strise of growth. 



This is a most interesting form, as it is the first species of the genus 

 from American rocks, and its occurrence in the Devonian limestones of 

 Nevada is such that, when finding only a few fragments of the spire, we 

 were led to consider it a land shell, the short, obtuse form recalling species 

 of the genus Pupa. 



S. Americana departs somewhat from the typical species S. Dannen- 

 bergii Braun 1838, (Neues Jahrbuch, Min. Geo. Geol. und Petrefak, p. 29S, 

 taf. ii, figs. B, 14) in having the aperture contracted and the inner lip more 

 expanded, but there are no differences that appear to be of more than spe- 

 cific value. 



Formation and localities. Lower Devonian of Atrypa Peak, and Brush 

 Peak, Eureka District, Nevada. 



This species is associated with Productus subaculeatus, Spirifera undifera, 

 Atrypa reticularis, Goniophora perangulata, Platyceras dentalium, P. carinatum, 

 Belleroplton perplexa, etc. 



Genus METOPTOMA Phillips. 



Metoptoma ? Devonica, n. sp. 



Plate xvii, figs. 2, 2 a. 



Shell conical, broadly rounded or truncated at the posterior margin; 

 uniformly rounded on the lateral and anterior margins; apex posterior and 



