T]]c Fauna of the Ma.vz'illc 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 

 growtli. which are abruptly bent backward at the carination on 

 the ui)i)er edge of the volution, which marks the notch in the 

 u])];er angle of the aperture. 



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

 Horirjon and locality. — Alaxville limestone. 

 Lower zone: Cut Xo. 4, Alt. I'erry-Fultonham. 



SPHAERODOMA SUBCORPULENTA-Whitfield 



1882. Macrocheiliis siibcorfulciitns. ^\'hitt^eld, Ann. X. Y. Acad. Sci., 

 Vol. II, p. 224. 

 Maxville limestone : Newtonville, Ohio. 

 1889. Sphccrodoma suhcorpnleiita. Keyes, Proc Acad. Nat. Sci. Phil., 



p. 30G. 

 1801. Macrocheiliis siibcor[^ii!eiitiis. \\'hitfield, Ann. N. Y. Acad. Sci., 

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

 Maxville limestone : Newtonville, Ohio. 

 1895. Macrocheiliis subcorpulentiis. Whitfield, Geol. Surv. Ohio, Vol. 

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

 Maxville limestone : Newtonville, Ohio. 



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

 A\']iorls three or three and a half in numljer, convex, and rapidly 

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



Fig. 2G. — Sphccrodoma sithcorpitlciita. 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. 



