Oct., 1845.] 281 



during several hours search along the shore, with the comparative 

 quantities in which they occur. 



Limneus elodes, (Say,) rare. 



Limneus Galbanus, (Say,) abundant. 



Planorbis bicarinatus, (Say,) abundant, 



Planorbis campanulatus, (Say,) abundant. 



Planorbis parvus, (Say,) abundant. 



Paludina decisa, (Say,) moderately abundant. 



Paludina: a minute species not determined; extremely abundant. 



Valvata bicarinata ? (Lea,) extremely abundant, 



Physa ancillaria, (Say,) abundant. 



Cyclas : a minute species not determined ; abundant. 



Fragments of Unios, which were too small to distinguish the 

 species. 



Mr. James D. Dana submitted the following 



General views on the Classification of Animals. 



In Cuvier's classification of animals, the division Radiata in- 

 cludes all invertebrated animals not comprised in either of the sub- 

 kingdoms, Articulata and Mollusca. Consisting thus only of refuse 

 species, and not limited by positive characters, as Owen states, we 

 should 'not expect that the group could be a natural assemblage. 

 No line of subdivision, however, has yet been made out, which has 

 mei with general favour ; yet greater precision has beengiven to our 

 views of the affinities that run through the animal kingdom, by ap- 

 pealing to the nerves, the seat of sensibility and sentiment, as a 

 basis in classification ; and in this manner the subdivisions have been 

 characterised as follows, by Dr. Grant. 



I. The Vertcbrata, having a brain and a spinal cord, constitute 

 the Spini-Vertebrata. II. The Mollusca, having the nerves 

 forming generally a transverse series of ganglia disposed around 

 the oesophagus, the Cyclo-gangliata. III. The Articulata having 

 no proper brain, and the main cord which runs the length of the 

 body, double, the Diplo-neura. IV. The Radiata, having a ra- 

 diate structure in the body, and the nervous ganglia arranged in a 

 circle, Cyclo-neura. 



34 



