272 PROCEEDINGS OF THE ACADEMY OF 



supplied with mitra-like folds. My specimen has seven or eight, 

 well developed. Consequently Mauritia is synonymous with Diba- 

 phics ; and it seems to me that the genus should be placed l'ather 

 with the Mitres than with the Cones. The differences between the 

 present genus and Dibaphus are small, and it is possible that the 

 two should be placed side by side, although I strongly suspect 

 that the resemblances are those of imitation rather than of true 

 relationship. 



Type P. crassilabra. 



ETJLIMID.E. 

 Iopsis, Gabb, pi. 11. fig. 6. 



Shell eulimoid, polished, spire elevated, suture nearly obsolete, 

 apex dextral ; no umbilicus ; columella slightly twisted and pro- 

 duced into a short lip-like canal, not emarginated. 



The ivory-like structure, obsolete suture, and whole general ap- 

 pearance of this little shell prove its close relationship to Uulima, 

 while its faintly twisted columella, extended to such a degree as 

 to produce a short though not notched canal, distinguishes it from 

 the other genera of the family. It resembles in form a miniature 

 Io, from which circumstance the name is derived. I have noticed 

 in some species of true Eulima a slight tendency to expansion of 

 the lip in advance, on the columella!' margin. 



I. fusiformis. 



STROMAIDiE. 

 Orthatjlax, Gabb, pi. 9, figs. 3, 4. 



Shell rounded fusiform, canal moderate, straight and regularly 

 tapering; adult shell enveloped over the whole spire by an exten- 

 sion of the inner lip ; posterior canal fissure like, formed by the 

 continued edge of the outer lip and running directly to the apex. 

 Outer lip apparently sharp and simple ; anterior notch oblique 

 and broad. 



The discovery of this genus fills an important break in the Ros- 

 tellarias, uniting the true genus Rostellaria, with Conrad's fossil 

 from Calyptraphorus. Unlike both of these genera the canal is not 

 * styliform, but robust and comparatively short, and its terminal 

 notch is formed by an almost rectangular truncation of the anterior 

 part of the outer lip. Like Rostellaria it has a straight posterior 

 canal, prolonged, however, further than is common in that genus. 

 The canal is similar in structure to that of Calyptraphorus, being 

 formed by a squamose plate, but in the latter genus it curves over 



