PLATE 8 5. 



Pa R e. 

 Fig. 1. Sc.u'iiitks Mandanensis 443 



l,o. A side view of a nearly perfect specimen. 



1,6. A peripheral and aperture view of same. 



1,0. A septum of same, magnified two and a half to three diameters. 

 Fig. 2. Scapiiites aiiyssinus 441 



•2,«. A side view of a specimen, with portions of the matrix attached. 



2, h. A septum, magnified two and a half to three diameters. 



Fig. 3. Scaphites Cheyennensis 437 



3, a. A side view of a perfect internal cast. 

 3,5. A peripheral and aperture view of same. 

 3, e. A part of the inner volutions of the same. 



3,rf. A fragment of the outer volution, containing one of those curious bodies usually called 

 an Aptichus, a part of one valve of which is broken away, so as to expose a jaw-like 

 different part of the same organ between the two valves. 



3, c. A septum of this species, magnified to between two and a half and three diameters. 



:!, /. An under-side view of the jaw- like piece of the Apl'ijchus, seen between the two valves of 

 the same in fig. 3, il. 



3, ;/• A side view of the same piece. 



3,/l. An upper view of the same. 



3, i. The Aptjjcliua, represented as it, would appear with the two valves opened otitrupon tin' 

 same plane; one of the valves being represented merely in outline to show the 

 position of the third jaw -like piece between ; also represented in outline. 



