13n Heli.r aspersd in C(ilif(jrni<i. 



persa gut mixed in with the ''Herald"" shells after the latter ar- 

 rived in England. Though the above hypothesis does not ex- 

 onerate the collectors of the "Herald" shells from the careless- 

 ness evident in their labels, it does favor them with an explana- 

 tion which places their habitat (as per label) within a compara- 

 tively near jn'oximity to the proper specific areas, which our 

 present knowledge indicates as correct. 



It is, however, really extraordinary that any author who had 

 seen the actual shells of the above American species and possess- 

 ing any knowledge of the relation of climate to coloration, should 

 have placed any of them without great hesitation and careful re- 

 search at so northern a station as this inquiry and a reference to 

 their works reveals. Take all the West American species named 

 in this jsaper, and their external aspect points conspicuously to 

 a habitat of minimum rainfall or moisture :, and the aspect of 

 the species, taken together as a whole, j)oints to a region of 

 aridity, or where aridity is the rule and not the exception. 



The time will come, and it is not creditable to the manage- 

 ment of museums anywhere, that it has not already arrived, 

 Avhen collections v/ill be arranged in double order, or under two 

 systems ; one, and the least important— now made the most so — 

 that of a classified arrangement according to the best authori- 

 ties ; the other, a geographical arrangement, — carefully placed — 

 according to the geographical distribution of animal life. Aside 

 from the light which such an arrangement would throw upon 

 many other points of great imi)ortance, — in the matter of cli- 

 matology a better knowledge of a great region would be jn'e- 

 sented at a glance than by all human records, or since civilization 

 reached the point of meteorological observation.* 



The various forms included under the names of //. areolata, 

 PandorcB, VeatcMi and levis, I regard as varieties of a single sj)e- 

 cies. The first two are found in great numbers on the shores 

 and in the region about Margaritaf or properly Magdalena bay, 



* In connection more or less directly with this line of investigation, see 

 Cooper " On the Law of Variation, etc. ; California Land Shells; Cal. Acad. 

 Proc, 1873, p. 121 and elsewhere. 



f Margarita is a large island, whose shores form a part of the honndary 

 of Magdalena bay ; hence the bay is sometimes so named by writers and 

 sailors. 



