NOMENCLATURE. 59 



merit ou a plane surface would fail, for the affinities radiate in 

 all directions, and the " net-work" to which Fabricius likened 

 them, is as insufficient a comparison as the " chain" of older 

 writers.* 



CHAPTER VI. 

 NOMENCLATIVE. 



THE practice of using two names generic and specific for 

 each animal, or plant, originated with Linnaeus ; therefore no 

 scientific names date further back than his works. In the con- 

 struction of these names, the Greek and Latin languages are 

 preferred, by the common consent of all countries. 



Synonyms. It often happens that a species is named, or a 

 genus established, by more than one person, at different times, 

 and in ignorance of each other's labours. Such duplicate names 

 are called synonyms ; they have multiplied amazingly of late, 

 and are a stumbling-block and an opprobium in all branches of 

 natural history. f 



* The quinary arrangement of the molluscous classes reminds us of the 

 eastern emblem of eternity the serpent holding its tail in its mouth. 

 The following diagram is offered as an improved circular system : 



[FISHES.] 



Di-brauchiata. 



Nucleo- Tetra- 



Opistho- Proso- 



Aporo- ^~\1 Pulmo- 



Pallio- Lamelli- 



Hetero-branchiata. 



[ZOOPHYTES.] 



f In Pfeiffer's Monograph of the Helicidte, a family containing seventeen 

 genera, no less than 330 generic synonyms are enumerated; to this list, Dr. 

 Albers, of Berlin, has lately added another hundred of his own invention ! 



