5G THE NAUTILUS. 



1 would select tlie same islaiul as tlie type locality oi" Ihiix 

 pandorae, credited by Dall to "Margarita Island," 1 believe, 

 though i*ilsbry selects the San Benito Islands, to the north- 

 west of Cedros Island, instead. 



Pilsbry selects San Bartolonie bay, on the peninsula, as tiie 

 type locality of Helix Irvis, but it seems to me that Santa 

 Margarita Island could be selected with equal propriety, and 

 this would give us these three "species" as from one "type 

 locality." It can never be exactly known where these types 

 were actually collected, so tliat any designation of a type 

 locality must be more or less arbitrary. 



My series of Helix arcokitu was all collected on Ma<^(lalena 

 Island, in a space perhaps a mile square, extending from the 

 ocean to the bay. The species was not confined to this area by 

 any means, and probably occurs in equal abundance over the 

 entire region around Magdalena bay. In places tlie ground 

 is white wdth the dead shells, and millions may be found 

 drifting in the adjacent sand hills on Magdalena Island. 



The scant desert vegetation, such as agave, fouciuiera, and 

 "other plants, often harbored considerable colonies of living 

 snails. The shells on the bushes would often be found in the 

 morning covered with sand, indicating that they burrow in 

 the soil, probably climbing the plants for feeding purposes 

 and some staying over time. All my specimens were obtained 

 from the plants, however, and not by digging. I doubt not 

 that every figure on Pilsbry 's two plates (Proc. Phil. Acad. 

 1913, plants 15 and 16, figs. 1 to 52) could be matched by 

 specimens living in the area of the square mile referred to. 



Many specimens were a solid chalky white, with no trace of 

 bands or color. Some have a strongly developed tooth; most 

 of the individuals show no trace of one. Some specimens, old 

 and mature, but usually rather small, were of a uniform pale 

 olivaceous-brown color, without signs of bands or other color, 

 that would answer well for Binney 's figure of Helix pandorae. 

 Some individuals Avere as elevated as Helix veatchii is figured 

 as being, and other shells are nearh' as depressed as Helix 

 Traskii. Young individuals would answer for Pfeiffer's fig- 

 ures of Helix decorata or H. levis. 



