Newell.] 482 [Jan. 18, 



about 10 mm. above the base. From this point the shell decreases 

 in size gradually and then rapidly rounds over to the apertures. 



The apertures are very like those of II. delphicolum but are pro- 

 portionally a trifle wider. 



The six dorsal lobes rise above the surface of the cast, showing 

 that they were prolonged upward by the shell, forming six short 

 tubes or funnels. The dorsal pair have a decided inclination tow- 

 ard the rear. 



The ventral aperture is prolonged into a tube projecting forward 

 and partially surrounded by a deep sinus. The septa as shown 

 by the base of the living chamber are but slightly concave. The 

 sutures are nearly straight with a low ventral saddle. The siphon, 

 as shown on the base of the living chamber, is slightly elliptical, 

 and in the type specimen is 4mm. in diameter and 5 mm. from 

 the ventral side. The surface markings are unknown. 



The several diameters of the type specimen are : dorsi- ventral 

 50 mm., lateral 46 mm., vertical 34 mm. A larger, less perfectly 

 preserved cast is nearly twice these measurements. 



Professor Hall has described (20th. Rept. State Cab. N. Y., 

 p. 410) a cast under the name of Go?nphoceras septoris which in 

 general shape is similar to this species. The possession of a sev- 

 enth dorsal lobe puts this, however, in the genus Septameroceras 

 (Hyatt). 



Locality. — Delphi, Ind. 



Similar to the above described t}^pe are several compressed and 

 distorted specimens from Wabash City. These consist of larger 

 casts of the living chamber and several closed chambers, com- 

 pressed laterally, poorly preserved and worn, yet in one case 

 showing the characteristic outline of the aperture and the shape of 

 the living chamber. Several of the smallest closed chambers are 

 missing, but enough remain to show that the shell increases rapidly 

 in size and is nearly straight, the dorsal side being slightly more 

 convex than the ventral. The general form is compressed, ven- 

 tricose and turbinate. The living chamber is about one-half the 

 length of the whole shell and its bulk from its turbinate form must 

 have been two or three times that of all the closed chambers to- 

 gether. The greatest diameter of the best preserved of these casts 

 ranges from 80 to 100 mm. 



The septa are strongly concave from compression, and average 

 7 mm. apart. 



