THE NAUTILUS. 63 



Length 12.25; width 8.00 ; aperture length 9.00; width 5.50 mill. 

 Length 11.25 ; width 7.75 ; aperture length 8.00 ; width 5.00 mill. 

 Length 9.75 ; width 7.00 ; aperture length 7.00 ; width 4.50 mill. 



Lymnsea randolphi nov. sp. 



Shell large, generally inflated, ovate ; whorls five to six, rounded, 

 inflated, distinctly shouldered ; spire short, pyramidal ; the first 3-4 

 whorls are small and regularly wound, but the last whorl abruptly 

 enlarges to more than four times the diameter of the preceding whorls, 

 causing the spire whorls to appear as (hough set upon a pedestal ; 

 sutures deeply impressed ; sculpture consisting of close-set, regular 

 lines of growth crossed by fine, impressed, spiral lines ; the surface is 

 malleated in many specimens and in some individuals there is a ten- 

 dency to form raised spiral ridges on the body-whorl ; aperture very 

 large, ovate, almost patulous, distinctly shouldered at the upper 

 part; columella without distinct plait, but covered by a heavy, erect 

 callus which overhangs the umbilicus; umbilicus deep, widely open; 

 color probably horny as in the majority of Lymnajidae, but chalky 

 white in the type specimens. Length 29.5, diam. 20, length of 

 aperture 19. mm. 



Habitat : Marsh Lake, near Dyea Valley, Alaska, collected by 

 Mr. P. B. Randolph. 



This is a very distinct species, not easily confounded with any 

 other. It has a superficial resemblance to Lymnsea mighelsi Binney, 

 but that species is imperforate or at most only very narrowly per- 

 forated. The shape of the spire, the rounded aperture and the open 

 umbilicus will easily distinguish it. 



Lymnsea atkensis Dall, is a narrow species with a long spire, a 

 very narrowly open umbilicus and wholly lacks its peculiar shouldered 

 whorls. The sculpture is more marked in randolphi. 



Cotypes are in the Academy of Natural Sciences of Philadelphia 

 and in the Chicago Academy of Sciences. 



A GLIMPSE AT THE SHELL FAUNA OF DELAWARE. 



BY S. N. RHOADS. 



Literature is strangely silent as to the fauna of the State of Dela- 

 ware. To remedy this in some degree, as well as to satisfy a long- 



