356 Miscellaneous. 



America'*, p. 177, are too elevated and globose for the typical areo- 

 lata ; but the larger figures faithfully represent H. Veatchii. Eleva- 

 tion and rotundity are insular characteristics in this group ; and 

 arcohita is comparatively depressed. It is found in considerable 

 numbers on the uplands around Magdalena Bay, which is on 

 the outer or ocean shore of the peninsula, in latitude about 24° 

 40' N. 



BuJimus pallidior, which is pretty generally distributed through 

 Lower California, from Cape St. Lucas northerly, has also errone- 

 ously been credited to San Diego in California proper. It is arbo- 

 real in its habits, at least during the winter season, and frequents 

 the Copaiva trees. It has been said to inhabit South America, 

 which is prohahly incorrect ; and the locality " San Juan," mentioned 

 in ' Land and Freshwater Shells,' on p. 195, where a good figure of 

 this species maybe seen, should be San Juanico, ^'hich is on the east 

 side of the peninsula, in latitude about 2V N. 



The great importance of particularity in habitat will be at once 

 perceived when I state that there are no less than three other locali- 

 ties on the west coast of America, north of the place cited, all of 

 which are referred to in various scientific works which have come 

 under my observ^ation as " San Juan ;" and there are perhaps as 

 many more San Juans south of that especially quoted herein, on 

 the westerly coast of America, in the Central and South- American 

 States. 



Attention is directed to the fact that the three species herein 

 mentioned as exhibiting extraordinary vitality, belong to geogra- 

 phical areas which receive only minimum rainfall, or which are, in 

 simple language, nearly rainless regions. 



Within such areas vegetation is exceedingly limited, even in 

 favourable seasons ; and the presence and growth of the annual 

 plants is, of course, dependent upon the rainfall : this last occurring 

 ini'requently, makes the food supply of landmoUusks and other 

 phytophagous or vegetable -eating animals exceedingly precarious. 



It is highly probable that a careful investigation in this direction 

 will lead us to the conclusion that the land moUusks which inhabit 

 arid areas have, through selection, adaptation, and evolution, become 

 especially fitted for the contingencies of their habitat, and possess 

 a greater degree of vitality or ability to live without food than re- 

 lated forms in what may be considered more favourable regions, and, 

 through and by reason of their long sleep or hibernation {more pro- 

 perly, cestivation), with its inactivity and consequent immunity from 

 any waste or exhaustion of vital strength, are enabled to maintain 

 their hold upon life when animals more highly organized would in- 

 evitably perish ; and we are furnished with an illustration, in the 

 instances cited, how nature works compensatively, when we institute 

 a comparison ^vith the opposite condition of activity and the food 

 required to sust-ain it. — Proceedings of the California Academy of 

 Sciences, October 18, 1875. 



• Smithsonian Misc. Coll. No. 194. 



