CLASSIFICATION. 
SYNOPSIS OF THE GENERA IN NATURAL POSITION. 
Hypothyris. Cyprina. Patella. Littorina. 
Terebratula. Circe. Acmeea. Assiminia. 
Argiope. Astarte. Pileopsis. Rissoa. 
Crania. Isocardia. Calyptreea. Truncatella. 
Anomia. Venus. Fissurella. Acme. 
Pecten. Pullastra. Emarginula. Tornatella. 
Ostrea. Donax. Puncturella. Jeffreysia. 
Mytilus. Ervilia. Haliotis. Barleeia. 
Dreissena. Tellina. Pleurobranchus. |Chemnitzia. 
Modiola. Syndosmya. Aplysia. Eulima. 
Crenelia. Serobicularia. Bulla. Aclis. 
Pinna. Lucinopsis. Bulla. Stylifer. 
Avicula. Anatina. Otina ? Scalaria. 
Unio. Corbula. Limnea, &e. Tanthina. 
Anodon. Spheenia. Limax, &e. Natica. 
Area. Pandora. Helix, &e. Lamellaria. 
Pectunculus. Solen. Conovulus. Velutina. 
Nucula. Solenicurtus. Pedipes. Rostellaria. 
Leda. Gastrocheena. Carychium. Murex. 
Galeomma. Saxicava. Spirialis. Cypreea. 
Lepton. Venerirupis. Trochus. Ovula. 
Lucina. Panopza. Phasianella. Marginella. 
Kellia. Mya. Scissurella. Octopus. 
Montacuta. Pholas. Valvata. Eledona. 
Turtonia. Teredo. Ceeum. Loligo. 
Cyclas. Xylophaga. Twrritella. Sepia. 
Pisidium. Cyclostoma. Sepiola. 
Cardiun. Dentalium. Paludina. Spirula. 
Mactra. Chiton. Neritina. 
If these positions are correct—and we have endeavoured to 
test them by the examination of near three hundred animals, 
all of which are confirmatory—we shall have placed the whole 
division of the Testaceous Mollusca on the sound basis of 
natural position. It is scarcely necessary to remark, that the 
subarrangement of the families, genera, and species, in their 
respective divisions, is of minor moment, and may almost be 
committed to the ad libitum of the naturalist; all that is 
necessary is, to collect similar objects, and deposit them, with- 
