1896. ] NEW YORK ACADEMY OF SCIENCES 139 
although no longer distinct in outline; in the light form there 
is the merest trace of this. 
These varieties are named by Sr. Quadras, a conchologist at 
Manila, as follows: 0, he agrees with me in regarding as the 
type. ‘“ Those with broad bands ” (presumably the lower mem- 
bers of the left-hand stem), var. euryzona. ‘Those entirely 
white ” (he perhaps refers to the right-hand stem, although none 
are entirely white), var. nana. ‘“ Those with yellow epidermis, 
with or without small bands” (probably 5’ and 6’) var. opaca. 
It is of especial interest to observe the order in which these 
bands disappear. Calling the bands in order from top to bot- 
tom, A, B and C, we have seen that A is the first to disappear, 
while C soon follows, and that B persists to the last unaltered. 
I did not find a single specimen which contradicted this rule. 
If two bands were present, they were invariably B and C, if 
only one, B. Now, it is interesting in this connection to com- 
pare Cochlostyla ovoidea with other members of the same genus. 
I have only examined about twenty-two species. The following 
are the results : 
In several species there was a single band occurring con- 
stantly or occasionally. This was invariably B. 
In one species there was either an entire absence of bands or 
B alone or B and C. 
Ina number of other species, the number of bands varied from 
one to three. In these cases the rule was adhered to with occa- 
sional exceptions. Finally, there were a few with all three in- 
variably and a number (about nine) entirely destitute of mark- 
ings. 
in the related genus Helix, which possesses typically five 
bands, the central one is the last to disappear. 
Another phenomenon of interest, illustrated by this set is 
that of correlative variation. In this species there seems to be 
some sort of a correlation between size and color. I measured 
the length of every shell obtained (538 in all), and found as a 
result that the average length of all those belonging to the cen- 
tral place (0) and to the whole left hand branch was 1.3 inches. 
The average length of the specimens belonging to the three ter- 
minal places of the right hand stem was J.47. Those interme- 
diate between 0 and the latter were intermediate in length. The 
greater size of the white shells 3, 4, 5 and 6, is quite noticeable 
in the figure. 
Such are the observable facts in regard to these shells. Their 
chief interest evidently lies in their relation to the general prob- 
lems of variation. With the few data which we possess, de- 
finite conclusions are premature, but it may not be unprofitable 
