144 THE NAUTILUS. 
GENERAL NOTES. 
THE DENTATR VARIETY OF Condus was first noticed by William 
Doherty in the Quarterly Journal of Conchology (Leeds), I, p. 344, in 
1870. He found it at several points near Cincinnati, Ohio, describ- 
ing thesheil as follows: ‘‘ The ‘teeth’ are placed as in Z. mudltiden- 
tatus Binn., and vary from one slight shapeless roughening of the 
inner surface of the outer whorl, to four large elongate teeth, radiat- 
ing from the umbilicus like the spokes of a chariot wheel. As is 
usual with gastrodont snails, these teeth attain their greatest de- 
velopment in the half-grown shell. From the chief locality of this 
variety I obtained 39 young fw/vus, of which 18 or nearly half 
were more or less dentate, while of 17 adult fulvus from the same 
place, one had in the next to the last whorl a single tooth, much 
flattened and eroded, while all the others were toothless. Hence I 
suppose that the teeth are gradually worn away by the motions of 
the animal. In Z. multidentatus, rows of teeth appear at an early 
age, and as often as the shell grows a quarter of a whorl a new row 
i } roduced, while the earliest is worn away. So the shell grows to 
maturity, always having three or four rows of denticles. In this 
variety of fulvus, however, this process seems to cease Jong before 
the shell reaches maturity and the last whorl is thus left without 
teeth.” 
POLYGYRA RICHARDSONI. var. LINGUALIS n. var.—Similar to the 
type in size (alt. 5-514, diam. 10-1114 mm.), very smooth and 
glossy, depressed above and below, though the base is convex, pro- 
jecting downward as far as or below the basal lip ; umbilicus filled 
by the preceding whorl «xcept for a minute axial puncture ; parietal 
fold of the aperture decidedly longer than in 7ichardsont, extend- 
ing to within one-half or one-third of a millimeter from the broad 
lamina on the outer lip, Whorls 4% (instead of 5). Rosario, 
near Mazatlan, N. W. Mexico, collected by M. A. Knapp, received 
from W. J. Raymond.—H. A. Pivspry. 
PLANORBIS DILATATUS Gould has recently been found by Hon. J. 
D. Mitchell in the Guadalupe river, in Victoria Co., Texas. ‘This 
is further south and west than previously recorded. 
