INVERTEBRATA. 403 



Family TURBINID^E. 



PALUDINA disscisa. Dekay quotes this as "the com- 

 monest species in New York;" and extra-limital species 

 lapidaria, subcarinata, as belonging to Pennsylvania. 



MELANIA. This genus abounds in Western and Southern 

 States. Dekay recites ninety-two extra-limital species, and 

 but few Northern species. A few of this family exist in 

 the waters of the mountain. This ends the list of Gastero- 

 poda. 



CLASS IV. ACEPHALA. 



(No head.) 

 This class are all aquatic. 



ORDER I. ACEPHALA TESTACEA. 



Embraces all bivalves and some multivalves. 



Family I. OSTRACEA. Marine.* 



Family II. MYTILACEA. Muscles. 



ANODENTA, (Brug.) Inhabit fresh water. 



UNIO, (Brug.) Inhabit fresh water. Now belonging to 

 the Family Naiades, (Lamark.) This family, in the details 

 of its organization, has been elaborated with wonder- 

 ful perseverance and zeal by Mr. Isaac Lea, President of 

 the Academy of Natural Sciences of Philadelphia. His 

 synopsis of the Family of Naiades is one of the most per- 

 fect monographs, on natural science, in existence, and like 

 all products of enthusiasm, bears upon it the stamp of de- 

 votion and love to the subject. His extensive catalogues 

 illustrate the results of the confusion of interminable syn- 



* Some eighty species of oysters have been described. Lamark 

 gives three species, borealis, virginica, and canadensis, to the Amer- 

 ican coast, and Dekay " confesses his inability to find more than 

 one, and that, under certain forms, cannot distinguish from the 

 common oyster of Europe." The oyster flourishes best (Dekay) be- 

 tween the 36 and 42 of north latitude. It is said to live "twelve 

 or fifteen years, and to be in best condition from the fourth to the 

 sixth year." 



