148 HABITS AND ECONOMY OP THE MOLLUSCA. 



was collected by the late W. M. Gabb in a thermal spring in the 

 Pueblo Valley, Oregon, the temperature of the water being above 

 blood heat. Limnsea, Anodonta and Neritina, are able to endure 

 water slightly brackish; Physa cfOrhignyana^ Lea, lives in the 

 salt marshes at Monterey, California ; and Pholas, Teredo, 

 oysters. Area and Modiola accommodate themselves to the fresh- 

 water streams of Asia and Malaysia. On the other hand the 

 numerous species of fresh-water Melanians of the Southern 

 rivers of the United States, seem to be arrested in their distri- 

 bution by the slightest admixture of sea-water, and do not 

 approach the coast. A little Limnsea {L. peregra^ var. geiseri- 

 cola) lives in the waters of the Geysers of Iceland (Morch). 

 The admixture of sulphurous and ferruginous elements in the 

 streams does not seem to prevent the multiplication of some 

 mollusks. Cardium edule has become extinct in the Chotts of 

 Algiers and Tunis, on account of excess of brine, although a 

 marine species ; yet the fresh-water genera Melania and Melan- 

 opsis have been collected from waters surcharged with salt so as 

 to be absolutely undrinkable, at the oasis of Ouargla, south of 

 Algeria (Tournouer\ 



The permanency of the shell-bearing races is effectually pro- 

 vided for by their extreme fecundity ; and though exposed 

 to a hundred dangers in their early life, enough survive to 

 re-people the land and sea abundantly. The mollusca exhibit the 

 same instinctive care with insects and the higher animals in 

 placing their eggs in situations where they will be safe from 

 injury, or open to the influences of air and heat, or surrounded 

 by the food which the young will require. 



" If anjT^ one imbued with the spirit of Paley or Chateaubriand, 

 should study these phenomena, he might discover more than the 

 ' barren facts ' which alone appear without significance to the 

 unspiritual eye ; he would see at every step fresh proofs of the 

 wisdom and goodness of God, who thus manifests His greatness 

 by displajang the same care for the maintenance of His feeblest 

 creatures as for the well-being of man and the stability of the 

 world." — Woodward. 



Economic Uses of Shells. We have spoken of shell-fish as 

 articles of food, but shells have other uses even to man ; they are 

 the toys of children, who hear in them the roaring of the sea ; 

 they are the pride of" collectors " — whose wealth is in a cone or 

 " wentle-trap ;" and they are the ornaments of barbarous tribes. 

 The Friendly Islander wears the orange-cowry as a mark of 

 chieftainship (Stutchbury), and it is somewhat rare to find a 

 specimen in collections which has not been bored through the 

 back for the purpose of suspending it ; and the New Zealander 

 polishes the Elenchus into an ornament more brilliant than 

 the " pearl ear-drops " of classical or modern times (Clarke). 



