PLATE 120. 



Page 



Pig. 1-7. Platyceras keflexum. 477 



1 a, 4. View of the upper side of the spire, and of the aperture of a small specimen. 



2 a. b. Similar views of a shorter form of the same species. 

 8. A larger specimen of the same species. 



4. A specimen in which tlie first volution of the spire is concealed. The surface shows some 



obscure marks of spiral plications. 



5. A brgc specimen in which the last volution is more than usually deflected, standing al- 



most at a right angle with the preceding volution. 



6 a, 6. Two views of a specimen in whicli the aperture is obtusely quadrangular. 



7 o, 6. A similar specimen with the preceding, wliere the last volution is less deflected than 



usual from the direction of the preceding volutions. 



Fig. 8. Platyceras? ( Platyostoma?) callosum. 478 



8 a. View of the back and upper part of the last volution. 

 8 b. View of the aperture, spire, and callosity of the columellar lip. 



