414 PROCEEDINGS OF THE ACADEMY OF [April, 
preceding. A prominent, whitish, inflated ridge, appearing like 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. Pl. 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 808, 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. 
