BALCH : LIST OF MARINE MOLLUSCA. 
147 
cussion, the form called by Yerrill A. similis is common'at Cold- 
spring Harbor on shelly bottoms below tide marks. Among them 
occur a few specimens not connecting well with the common form 
and answering to Yerrill’s interpretation of A. avara. Judging 
from the general character of the fauna, it might be permissible to 
predict that the commoner form is the more southerly. 
Astyris lunata (Say). Yerrill (’73), p. 645. Columbella l. 
Smith and Prime (’70), p. 398. S. 
Common everywhere below tides. Also on Ulva, etc. Yery 
conspicuous for its extreme variability of color-pattern and its activ¬ 
ity. 
var. gouldiana Ag. MS. (Stimps.), = Buccinum viheatleyi 
DeKay, is tolerably common. 
i 
Nassidae. 
JVassa obsoleta (Say). Smith and Prime (’70), p. 397. llyan- 
assa o. Yerrill (’73), p. 641. 
Abundant everywhere, especially on mud flats where it is dom¬ 
inant. 
JVassa vibex Say. Smith and Prime (’70), p. 397. Yerrill (’73), 
p. 640. S. 
Uncommon. Capriciously distributed among JV. obsoleta , from 
which it is not always readily distinguishable. A fairly well- 
marked variety, perhaps = IV. fretensis Perkins (’69), occurs, occa¬ 
sionally in some numbers, on eel-grass. 
JVassa trivittata Say. Smith and Prime (’70), p. 397. Tritia t. 
Yerrill (’73), p. 641. 
Abundant in proportion as the situation becomes too exposed for 
JV. obsoleta , and in deeper water. 
Turbinellidae. 
Fulgur cariea (Linne). Yerrill (’73), p. 640. Pyrula c. 
Smith and Prime (’70), p. 398. S. 
Common below tides, but less common than the following. 
Fulgur canaliculata (Linn6). Pyrula c. Smith and Prime 
(’70), p. 398. Sycotypus c. Yerrill (’73), p. 640. S. 
Yery common, but not perhaps abundant, from "2 fathoms out. 
