142 THE NAUTILUS. 



tent of melanism as the var. nigricans of C. eglatt'na, but without a 

 tendency to rostration. 



C. TIGRIS var. ROSSITERI. Is characterized by the dorsal surface 

 being a beautiful orange, the scattered brown spots being few in 

 numbers. 



C. VITKLLUS var. SUBROSTRATA. Based on a specimen showing 

 a tendency to rostration. 



C. ERRONES L. Under this species three varieties are recognized, 

 var. ovum Gme\.=sophise Brazier, a color var. afbida, entirely white 

 except for light spots of brown on each side of the extremities, var. 

 pallidior, with dorsum very pale, base recurved, callus very thick, 

 white, without spots at the extremities.- 



C. WALKERI var. ROSSITERI is based on Luponia bregeriana 

 Rossiter (1882) not Crosse (1868). 



C. ZIC/AC var. DECOLORATA. Specimens tending to albinism. 

 C. mf Hart's Gmel. and C. ebunia Barnes are both considered varieties 

 of C. latnnrcki ; but in uniting these forms why make C. laniarcki 

 Gray 1824 the species and 0. miliaris Gmel. 1790 a variety? 



C. POHARIA. var. INSIGNIS is unusually shining or seemingly 

 translucent, dorsal region orange, without spots, base beautifully 

 tinged with violet. C. W. J. 



BIOMETRIKA, a new journal for the statistical study of biological 

 problems (Cambridge, England) contains several papers on mollusks. 

 In vol. 2, part 1 (Nov., 1902), Miss Abigail C. Dimon has studied 

 at length the variation and correlation of Nassa trivittalanml obsoleta 

 from Cold Spring Harbor, Long Island. She discusses the influence 

 of density and stillness of water on depauperization. Both species 

 were found at that locality to be smaller than normal type, this be- 

 ing attributed to lack of density of the waters of Long Island Sound 

 as compared with the open ocean. While this explanation may 

 apply to N. trivittata which is a snail inhabiting open beaches, it is 

 certain that the small size of N. obsoleta is not thus to be explained, 

 because this h a species of the salt meadows and inlets, and the 

 largest individuals we have ever collected were taken in a stream in a 

 mud-flat, which ran fresh at low tide, and being far from the open 

 ocean, could not have been very dense when submerged at high tide. 

 There is great need for improved mechanical devices for rapidly de- 

 termining quantitatively the various characters both of form and 



