THE NAUTILUS. 
89 
VERTIGO MORSEI, n. sp. 
BY DR. V. STERKI. 
Shell large (for the group), cylindrical-turriculate, with a rather 
acute apex, imperforate rimate, with few obsolete striae of growth, 
shining, translucent; whorls six, rather slowly and regularly in¬ 
creasing, the last scarcely higher than the penultimate and rather 
narrower, somewhat sloping towards the base, slightly ascending at 
the aperture; suture deep; aperture lateral, scarcely oblique, com¬ 
paratively small, inferior and palatal part well-rounded, the latter 
with an angular impression and slightly protracted in about its 
middle, the upper half more strongly curved, peristome everted ; on 
the palatal wall, at some distance from and parallel with the mar¬ 
gin, a moderate crest, behind it a deep and large impression over 
the palatal folds, and in front of it a groove corresponding with the 
impression at the auricle ; inside the crest there is a distinct callus 
of the same color as the shell ; apertural lamellae and folds typic¬ 
ally nine: three on the parietal wall (the same as in V. ovata ), the 
largest whitish ; two on the columella, the superior strong, vertical 
above, then in an angle turning horizontally, the inferior horizontal, 
lamelliform, thin, high and directed obliquely upward; basal small, 
sometimes double, rarely 0 ; palatals high, and rather long, curved 
and directed upward; suprapalatal small, nodule-like. 
Size: alt. 2 - 7, diam. 13 ; apert. alt. 09, lat 0 - 8 mill. 
Soft parts not examined. 
Habitat: Kent County, Michigan. 
This magnificent Vertigo has been collected by Dr. DeCamp and 
kindly sent for examination by Mr. Bryant Walker. There were 
seven specimens, all fully mature, well-formed and almost exactly 
alike. Vet there are some slight differences, as they may be found 
in all forms of this group : in one example the inferior parietal tooth 
is wanting, in another the basal only trace-like, and in a third the 
same is double, as frequently found in V. ovata. With the latter 
species, V. morsel has much resemblance, especially in the aperture : 
the configuration and the “teeth” are the same, but the inferior 
columellar, and the two principal parietals, are rather larger, and 
markedly directed upward. The main difference is in the number 
and relative size of the whorls: while in V. ovata they are five, and 
rapidly increasing, the last predominating; in our species there are 
six, slowly increasing, the last, and consequently the aperture, com- 
