1882. 181 Trans, N. V. Ac. Sez. 
teeth. The modern “ white shark” is some five feet long and if 
the proportion was the same between the size of the teeth and the 
whole body in the ancient Carcharodon, its size must have been 
fully fifty feet. It is noteworthy that very large teeth of similar 
character, but in quite a fresh condition, were dredged up in the 
depths of the Pacific by the “‘ Challenger” party; which fact would 
indicate that this species, or one closely akin to it, had survived in 
the deep waters, at least until quite recently. 
He also exhibited an ingot of aluminium, two inches by six, ob- 
tained by a new process, at much lower rates than had heretofore 
been possible, and remarked upon the many important uses for 
aluminium, if its cost could be reduced. 
The following papers, by Mr. THomas BLaNnp, were read by 
title : 
I. DESCRIPTION OF TWO NEW SPECIES OF ZONITES FROM TEN- 
NESSEE. 
II. NOTES ON THE DISTRIBUTION OF GENERA OF TERRESTRIAL 
MOLLUSKS IN THE WEST INDIES. . 
Dr. WeEsLEY MILLER read a paper entitled : 
THE PREVENTION OF TUBERCULAR DISEASE IN MEN AND ANI- 
MALS BY VACCINATION. 
He discussed the general theory of inoculation and vaccination, and 
referred to experiments made by himself, and to be further carried on, 
as to the reduction of virulence attainable by artificial propagation of 
virus through many generations, in the bodies of domestic animals. 
Dr. N. L. Britton read the following paper : 
ON SOME LARGE POT-HOLES, NEAR WILLIAMSBRIDGE, N. Y. 
Tne “ pot-holes”’ which I shall attempt to describe were first brought 
to my notice by the late Prof. A. WooD. They are located on the 
western bank of the Bronx River, about midway between Bronxdale 
and Williamspridge, Westchester County, New York. They are near 
the western end of a now dismantled and impassable bridge, with stone 
abutments, and in the northern part of a hemlock grove which fringes 
the stream for about a mile below. It is one of the most picturesque 
spots in the vicinity of New York City, and a walk along the little river 
from Bronxdale to Williamsbridge is always enjoyable. 
The Bronx “ River,” as it is called, though the term gives it an im- 
portance which it does not possess, is a stream about 40 to 50 feet 
