Monograph of the Gasteropoda. 313 



but at Vei'sailles, Indiana, I found specimens having a height of about 

 /^th inch ; breadth, -^^t\\ inch. It is a very common fossil. 



Cyclora (?) parvula — (Hall). 



Shell small ; spire elevated, conical ; volutions three, increasing 

 moderately in size to the last whorl, which rapidly enlarges, the upper 

 ones being nearly round, and the lower one angular at the middle ; 

 suture very deep, in* consequence of the convexity of the whorls; aper- 

 ture nearly circular, slightly projecting downward, and angular at the 

 outer margin ; umbilical perforation very small; surface smooth. 



It varies considerably in size ; a medium specimen has a length of 

 about e\th inch; breadth about /^th inch. 



Found back of Plainville, on Vine street hill, at Versailles, and at 

 other places throughout the Cincinnati Group, associated with 0. 

 minuta. It is, however, comparatively rare. 



Cyclora Hoffmanni — (S. A, Miller). 



Fig. 33. — Cyclora Hoffmanni. Magnified about ten diameters. 



Shell very small ; .spire elongated, volutions five or six, round, in- 

 creasing very gradually in size ; suture deep, in consequence of 

 the great convexity of the whorls ; aperture nearly circular, projecting 

 slightly downward ; surface smooth. 



Length of a medium sized specimen, -^oth inch; width less than 

 •^^th inch. The length is nearly three times as great as the width. 



It is found in the run back of Plainville, associated with (7. minuta 

 and C. parvula. 



The specific name is given in honor of John W. Hofiinaun, of Cin- 

 cinnati, a member of the Society of Natural History, and active col- 

 lector of fossils. He found the Anomalocritius incurvus (which is fig- 

 ured in the Ohio Paleontology, from my cabinet), and more recently he 

 discovered an Asaphas (Isotelus) megistos, about eleven inches in 

 length and seven inches in breadth. 



