THE NAUTILUS. 21 



bilicus 3.3mm.; 4 whorls. Whetstone Range. Most speci- 

 mens taken this year are larger than the type lot, collected by 

 Ferriss and Daniels in 1914. 



Sonorella insignis, n. sp. The shell is much depressed, rather 

 solid, openly umbilicate. Band is broad with pale borders. 

 Surface roughened by low wave-like ribs in the direction of 

 growth-lines, and microscopic incised lines. Aperture small. 

 Peristome very little expanded, blunt. Alt. 9.8, diam. 20.5 

 mm. ; 4% whorls. Whetstone Range. One of the finest Sono- 

 rellas collected in 1919, recalling S. dalli by its depressed form. 



MOLLU8CA OF FORRESTEB ISLAND, ALASKA. 



UNIVALVES (Continued from page 69). 



BY GEORGE WILLETT. 



Tornatina carinata Gld. Tornatina culcitella Gld. Cylichna 

 alba Brown. These three species were taken occasionally in the 

 dredge, the latter being the most uncommon. 



Dentalium pretiosum Nutt. Very plentiful in 10-40 fathoms. 



Dentalium dalli Pils. A few young specimens secured in 50 

 fathoms. 



Limacina pacifica Dall. Appeared swimming in the water in 

 great numbers at times during calm weather. Extensively 

 eaten by several species of fish. 



Siphonaria thersites Cpr. Abundant in some localities, mostly 

 in short moss growing on the rocks considerably above low tide 

 line. 



Crassispira perversa Garb. Dredged occasionally in 40-50 

 fathoms. 



Crassispira rotula Dall. More plentiful than the last in about 

 same depth. 



Crassispira (Suavodrillia) sp.? A specimen dredged is now in 

 National Museum. Stated by Dr. Dall to be undescribed. 



Mangilia oldroydi Arnold. Mangilia eriopis Dall. Mangilia 

 crebricostata Cpr. A very few specimens of each of these three 

 species were taken in the dredge. 



