THE NAUTILUS. Ai 
Pis. vesiculare n. sp. 
Mussel small, ovoid, very inequipartite, somewhat oblique, strongly 
inflated; beaks very posterior, moderately prominent; margins all 
well rounded, or the scutum forming a very slight angular projec- 
tion; color yellowish to brownish-horn ; surface slightly striated, 
polished, often with a few coarser lines of growth; shell thin, trans- 
lucent ; nacre rather glassy, colorless; hinge rather small, markedly 
short; cardinal teeth lamellar, the right moderately curved with its 
anterior end thicker ; anterior left distinctly directed upward, curved, 
often angular, posterior oblique, moderately curved ; groove between 
them narrow and deep ; lateral teeth situated very close to the car- 
dinals, short, especially those in the left valve abrupt, high; liga- 
ment short. 
Size: long 2°3, alt. 1°9, diam. 1°7 mill. 
Habitat. Michigan. 
More than fifteen hundred specimens were seen during the last 
year, collected at Grand Rapids, Michigan, by Mr. L. H. Streng 
about ten years ago, and all were remarkably uniform in shape and 
appearance. Yet I hesitated to announce the form as a new species, 
thinking it might be a variety of P. ventricosum Prime. But later 
it has been seen from various other places, as Lake Michigan, Hess 
Lake, “ Michigan,” in one instance named “ P. rotundatum,” from 
which it is very different by its beaks situated posteriorly, while in 
rotundatum they are almost in the middle. 
P. vesiculare can be mistaken only for P. ventricosum Pr., from 
which it differs by the following characters: it is longer, less oblique; 
more regular in form, being more regularly though less inflated, the 
beaks are much less prominent; the surface shows less coarse and 
irregular lines of growth. It is somewhat variable in size, measur- 
ing 2°1-2°7 millimetres in length, and in being slightly more or less 
inflated. 
A NEW VARIETY OF PUNCTUM. 
BY H. A. PEESBRY- 
Punctum conspectum var. pasadene n. var. 
Shell resembling P. conspectum Bld., but more widely and openly 
umbilicated, and without spaced riblets, or with them very slightly 
indicated. 
