LAND SHELLS OF THE GENUS BULIMULUS IN LOWER CALIFOR- 

 NIA, WITH DESCRIPTIONS OF SEVERAL NEW SPECIES. 



BY 

 \Vii.MAi\i Healey Dall, 



Ilcnorary Curat v of the DepartvienI of Mollusks. 

 (Willi I'liiics i.XM :iim1 KXXii.) 



The peninsula of Ijower Calitbrnia is known as the lionie of several 

 interesting species of the j»enus liulimKlus, including what is, perha])S, 

 the largest s])e(;ies of th<; genus, />*. montcziima. As niuch of the penin- 

 sula, in its arid highlands, recalls the anah)gous districts of Peru and 

 Chile, so the land shells, especially the Bulimuli, bear iu their external 

 characters the imprint of a similar (Mivironnient, which liiis gone so far 

 thiit, in one or two cases, the similar species of California and Peru 

 have been referred to the same species. An examination of a good se- 

 ries shows, though this opinion proves to be mistaken, that there was 

 reasonable ground lor it in the remarkably simihir effects produced by 

 the similar environment acting uixrn plastic forms of the same genetic 

 history, in the two widely separated legions. The reception of an in- 

 teresting series of si)ecimens from the California Academy oi' Sciences, 

 collected by an exploring expedition sent out by them, and the at- 

 tempt to name them, and simultaneously to review the s]»e('ies already 

 well rei)resented in the national collection, gradually led to the study 

 embodied in the present i)aper. 



The first species of the group from this region was described by Sow- 

 erby in l^'.V.i; others were named by Gould in the l>oston Journal of 

 Natural History in 1852-53. An account of most of the oMer species 

 maybe found in the "Land and Fresh-Water Shells of North America," 

 Part I, by Binney and Blaiul, ])[). 191-208, 18G1). Later references to 

 them a])pear in the great work by Crosse and l^Mscher on the land and 

 fresh-water mollusks of Mexico, and in papers by IJr. J. (J. Cooper in 

 the i)ro(.'eedings of the (California Academy of Sciences, second series, 



HI, i)p. 0!»-10;>, 207-217 and , Avith Pis. xiii and xiv, and also in 



Zoe, Vol, III, p. 11, April, IS'J2. The figures on the plates above men- 

 tioned are, unfortunately, not as characteristic as might be wished. 

 There is also a short paper by the writer on />. profmn, in the Nau- 

 tilus, of July, 1893. 



Pr()C('0(liiif;.s Niitioiial Mus<niiii, \'o\. XVI— No. 958. 



639 



