34 PROCEEDINGS : BOSTON SOCIETY NATURAL HISTORY. 
Purpura lapillus (Linne). 
Most abundant on the outer rocks everywhere. A most variable 
species; series from different islands show great variations in size, 
color, and proportion. The sharply ridged form, P . imbricata of 
Lamarck, is found in the tide pools on Shag Point at Ironbound 
Island ; and at Yellow Island a bright yellow form predominates 
over the duller colored individuals. The yellowish and reddish rocks 
give the name to the island. In sheltered places it grows to large 
size. We have found specimens 1 j inches long. 
Scala groenlandica (Perry). 
Scalaria groenlandica , Gould, ’ 70 , p. 314. 
Rather common at stations 4, 8, 10, and 17. Portions of the live 
animal on removal from the shell are of a most beautiful purple 
color. The shells here are pure white and the operculum black. 
Turbonilla sp. 
Only one dead and very worn specimen found which suggests 
“ Turbonilla nivea” Stimpson, dredged at station 24. 
Menestho albula Moller. 
Rather common, dredged at stations 17, 19, and 22. 
Odostomia modesta (Stimpson). 
Rare, a few dredged at station 6. 
Odostomia producta (Adams). 
Only one dead and worn specimen dredged at station 6. 
Trichotropis borealis Sowerby. 
Common at stations 10, 11, and 17. 
Mesalia acicula (Stimpson). 
Turritella acicula , Gould, ’ 70 , p. 319. 
Not rare though of small size. Dredged at stations 5 and 12. 
Mesalia erosa (Couthouy). 
Turritella erosa, Gould, ' 70 , p. 317. 
Rare, only one dead and eroded specimen, dredged at station 21, 
but fine large live specimens dredged in 15 fathoms, mud, 500 yards 
south of Egg Rock light. 
