414 PROCEEDINGS OF THE ACADEMY OF [Apiil, 



preceding. A prominent, whitish, inflated ridge, appearing Hke a 

 second peristome, occurs behind the peristome. Aperture propor- 

 tionately more contracted than that of V. ovata; set with a parietal, 

 an angular and a columellar lamella; and with two palatal and a basal 

 fold. The palatal folds are prominent, the upper one slightly double- 

 topped, the lower one more immersed and entering spirally. The 

 parietal lamella is stout and blunt; the angular lamella smaller and 

 thinner; the columellar lamella and the basal fold low and blunt. 

 Peristome rather thin, expanded, and notched opposite the upper 

 palatal fold, as in V. ovata. 



Alt. 1.7, diam. .9 mm. 



In one specimen there appears a slight suprapalatal denticle. A 

 considerable number of smaller, more globose specimens seem to belong 

 to this species. One of these from locality 806 measures 1.4 x .9 mm, 



I have assumed that this species is more closely related to V. ovata 

 than to any of the species reported from the West Indies. 



Localities 806 and 807 ; the type from 806. 



This is the common fossil Vertigo. 

 Vertigo marki n. sp. PI. XXXVI, fig. 7. 



Shell rimate, ovate, yellowish-corneous, faintly striatulate; whorls 

 nearly 5, rather convex. Apex obtuse, but not rounded like that of 

 Vertigo numellata. The inflated ridge inconspicuous, whitish, crowded 

 close to the peristome. Aperture ovate, much longer than in Vertigo 

 numellata, set with four denticles, of which the parietal lamella is the 

 largest. The lower palatal fold denticular, smaller than that of Vertigo 

 numellata and less immersed; the upper palatal fold minute; and the 

 columellar lamella broad and low. The peristome is expanded, white, 

 strongly thickened within, hardly notched at the upper palatal fold. 



Alt. 1.9, diam. 1 mm. 



Named in honor of Dr. E. L. Mark, of Harvard, Director of the 

 Bermuda Biological Station for Research. 



This species is somewhat suggestive of V. tridentata, but is a little 

 slenderer, with a longer aperture, and a heavy white peristome. 



Locality 806; doubtful specimens from 807. 

 Bifidaria rupicola Say. 



One specimen each from localities 806 and 80S, and several recent 

 specimens. Dr. Pilsbry reminds us that the Bermudian form has a 

 thicker lip than the others of this species. Cuba, Florida. 

 Bifidaria servilis Gld. 



One specimen from locality 818, and a few recent. Cuba and other 

 West Indian islands. 



