THE NAUTILUS. 55 



HELIX AKEOLATA. 



BY C. R. ORCUTT. 



The month of March, 1917, was spent by the writer almost 

 entirely on Magdalena Island, Baja California, Mexico. One 

 day was spent on Santa Margarita Island, separated from 

 Magdalena Island by a channel about ten miles wide, which 

 serves as the main entrance to Magdalena bay to-day, which 

 can be entered, though by small boats, by the two other chan- 

 nels north and south which separate these islands from the 

 peninsula. By dropping the "Santa," as is often done in 

 conversation, we have "Margarita Island," so often men- 

 tioned in shell literature, which in turn lent its name to the 

 bay which it helps to protect — hence ' ' Margarita bay, ' ' where 

 W. Harper Pease had collected for him seventy-four species 

 of mollusks, as reported by Carpenter. 



The industry in orchilla {Roccella tinctoria), for dye-stuff, 

 that was developed about forty years ago, when, I am told, 

 as much as a million dollars worth of this lichen was ex- 

 ported to Germany around the Horn in a single year, led to 

 the present settlement on Magdalena Island. Mining for 

 magnesite has now led to another settlement on Santa Marga- 

 rita Island in recent years, though it seems probable that this 

 settlement really antedated that on Magdalena Island. 



Helix areolata was the only land shell reported by Car- 

 penter from Margarita bay in the Pease collection. In vain 

 I searched for the Pupas, found so abundantly further nortli 

 at San Quintin bay in 1886, on Roccella tinctoria, but I doubt 

 not these may yet be found in the vicinity of the bay. on the 

 peninsula if not on the islands, by some more persistent ob- 

 server upon more thorough exploration of the bay shores. 

 One specimen, not at hand, that may have been Assiminea 

 calif ornica, two dead specimens of Pedipes (prol)ably P. lira- 

 tus), and numerous living Melampus olivaceus were found. 



Pilsbry is no doubt right in taking Magdalena bay as the 

 type locality for Helir areolata (see Proe. Phil. Aead. 1913, 

 391), but I would select Santa Margarita Island as probably 

 the exact location. 



