PLATE 61. 



Fig. 1. Platyceras platystomum. 320 



1 a. The left posterior side of a specimen, which is crushed on the upper side. 

 1 b. The anterior side of the same, the distortion being due to pressure. 

 1 c. A young individual which is somewhat distorted by prcssura. 



Fig. 2. Platyceras ventricosus. 



2. View of the aperture of a specimen of this species. A part of the preceding volution has 

 boon removed by weathering. 



Fig. 3. Platyceras pileiforme. 327 



8 a. The upper side of a specimen in which the apex is partially broken ofl'. [ The minute 

 volution is seen on the specimen, though not represented in the figure.] 



3 i. Profile view of a young specimen. 



Fig. 4. Platyceras perlatum. 328 



4 a. View looking upon the summit of the fossil. The indentation near the summit may have 

 been due to the involution of the apex of the shell, which afterwards became solid, a.s 

 the apex of the cast is not broken. 



i b. An oblique postero-Iateral view of the specimen. 



