Description of a Xev--< Genus and Eleven New Sj^ecies. 105 



one-huudredths of an inch; length of the cardinal line about thivt}^ oue- 

 hundredths of an inch; convexit}- about thirty one-hundredths of an 

 inch. 



This shell is distinguished from other species by its high incurved 

 beaks, closely truncated, anterior margin, and numerous radiating costre. 



The specimen illustrated was collected by Mr. George L. Vallandig- 

 ham, at one of the quarries on the hills back of the city of Cincinnati. 



Cyrtoceras am(exu3I, n. sp. [Plate III., fig. 8.] 



[Ety — Amcemts, pleasant, welcome.] 



Shell large, gentlj^ arched, and verj' gradually tapering; section 

 slighth' elliptical, the dorso-ventral diameter being a little more than 

 the transverse. Body chamber contracted toward the front. Septa 

 moderately arched. In the specimen figured, the body chamber is fol- 

 lowed by six thin chambers before reaching what appear to represent 

 the mature size; another specimen shows only five of these thin cham- 

 bers between the bod}- chamber and the mature sized shell chambers. 

 Where on the back of a shell the septa are nearl}^ 2-lOths of an inch 

 distant, the transverse diameter of the shell is 1 3-lOths inches, and 

 the dorso-ventral diameter 1 5-10 ths inches. Measuring on the side, how- 

 ever, the transverse diameter of the shell is equal to the thickness of 

 almost nine shell chambers. Siphuucle small, and situated very close 

 to the margin on the dorsal or outer side of the shell. Outer shell and 

 surface unknown. 



The specimen illustrated has a dorso-ventral diameter of 1 4-lOths 

 inches, and transverse diameter a little over 1 2-lOths inches. It con- 

 tains twenty three chambers, including the thin ones, between the 

 body chamber and the broken end in a length of 2^ inches. 



I collected the specimens at Richmond, Indiana, in the upper part of 

 the Cincinnati Group, and near the top of the blufl^s which abut the 

 river. 



Angellum, n. gen. 



[Ets.—Agiyos, a pail ; ellics, diminutive.] 



Shell equivalved, elongated from the cardinal line toward the base 

 and sub-cylindrical ; umbones prominent ; beaks incurved over the 

 cardinal line ; more or less winged posteriorly ; surface marked by 

 concentric lines. 



Surface of the shell, hinge line and muscular impressions not 

 determined. 



Several casts of the interior have been found in the upper part of the 

 Cincinnati Group, not referable to any genus known to the author; they 

 are quite perfect, and seem to deserve a name, but it is not without 



