The Fauna of ihc MaxvUlc Limestone. 401 



slightly ventricose ; suture canaliculate, the groove margined by 

 a slight sharp carination at the upper edge of the volution ; aper- 

 ture sub-ovate ; surface smooth, or marked with fine lines of 

 growth, which are abruptly bent backward at the carination on 

 the upper edge of the volution, which marks the notch in the 

 upper angle of the aperture. 



Length, .18 of an inch [Hall. 1883]." 

 Hori::on and locality. ■ — Maxville limestone. 

 Lower zone : Cut No. 4, Mt. Perry-Fultonham. 



SPHAERODOMA SUBCORPULENT A— Whitfield 



1882. Macrocheilus suhcorpulentus. Whitfield, Ann. N. Y. Acad. Sci., 

 Vol. II, p. 224. 

 Maxville limestone : Newtonville, Ohio. 

 1889. Sphcerodoma sitbcorpidenta. Keyes, Proc Acad. Nat. Sci. Phil., 



p. 306. 

 1891. Macrocheilus subcorpulentus. Whitfield, Ann. N. Y. Acad. Sci., 

 Vol. V, p. 591, pi. 14, fig. 14. 

 Maxville limestone : Newtonville, Ohio. 

 1895. Macrocheilus subcorpulentus. Whitfield, Geol. Svirv. Ohio, Vol. 

 Vn, p. 478, pi. 10, fig. 14. 

 Maxville limestone : Newtonville, Ohio. 



Description. — Shell small, cone-shaped, with rounded base. 

 Whorls three or three and a half in number, convex, and rapidly 

 increase in size so that the body whorl is much larger than the 



Fig. 26.: — Sphcerodoma subcorpulenta. A view of a specimen showing the 

 aperture.- (After Whitfield.) 



rest of the shell. Sutures distinct, but not deeply grooved. 

 Aperture ovate, acute above and rounded below. Columella not 

 prominently developed. Surface of the shell seemingly smooth. 

 Length 11-14 mm.; width 5-8 mm. 



