CERION, GROUP XI. 257 



In form thorndikei Maynard (pi. 40, figs. 16 to 19) tire size is re-^ 

 duced, the cone usually long, and the color faded, sometimes even 

 white, the dark blotches being much reduced in size, number and 

 intensity, and chiefly confined to the interstices. The riblets are- 

 white, and there is but little or none of the rich tawny color which* 

 adorns the type form. Length about 18, diam. 8 mill., riblets 23-26 1 

 on penult, whorl. This form occurred on the east side (chiefly) of 

 a path across the cemetery mentioned above* about midway between 

 the gate and a hill in the cemetery. Thorndikei is merely a small 

 or somewhat dwarfed form of curtissii. It occupies an area of about 

 100 square yards, surrounded on all sides by that of curtissii.. 

 Among the larger shells there are some very small, length 14-15, 

 diam. 7^-8 mill., with 7-| whorls (fig. 19). 



Form cinereum Maynard (pi. 40, fig. 20 ; pi. 41, figs. 21, 22, 23). 

 Shape varying from that of ordinary variant to somewhat stouter. 

 Riblets often stronger, about 25 on the penult, whorl. Whorls 9^ to 

 10. Aperture dull brown inside, the peristome narrowly or hardly 

 expanded, scarcely or but little thickened. Riblets white or pale, 

 the intervals various shades of brown, or largely invaded by white 

 tracts. Length 29, diam. 11 mill., or somewhat smaller, -length 26,. 

 diam. 10^ mill., down to 23 x 9-J mill. 



Hog Islan-d, Nassau Harbor, along the shore of Middle Bay^ 



Some specimens, Mr. Maynard's " form no. 2 " (fig< 24) are 

 heavily mottled with black-brown and ochre, the ribs still mainly 

 white. These occur east of the type locality, adjoining it. Larger, 

 heavier shells than the type but similarly colored, occur northward 1 

 (fig. 22). On the north- side of Hog Island, among some dwarf 

 palms growing directly back of the beach ridge, a stouter form, 

 robusta Maynard, with 9 whorls, length 28, diam. 13| mill, occurs. 

 I can see no difference deserving a name in the specimens. In a 

 restricted area on the borders of a field nearly on the eastern point 

 of Hog Island the form called tracta by Maynard occurs (pi. 41,. 

 figs. 25, 26, 27). The interstices are chiefly dark, ribs white. Size 

 varying from 19 to 28 mill. long. Many of them are absolutely in- 

 distinguishable from Maynard's " form no. 2 " of cinerea. 



On shrubs along the rocky northern shore of the western half of 

 Long Key (about a mile east of Hog Island), a form called S. cinerea' 

 mutata Mayn. occurs. It resembles cinerea of Hog Island in every- 

 thing but distribution (pi. 41, figs. 28, 29, 30), the las-t figure repre- 

 senting Maynard's " form no. 1." 



