48 MANUAL OF THE MOLLUSCA. 



NOMENCLATUEE. 



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 diflPerent 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 opprobrium in all branches 

 of natural historj'-.* 



One very common estuary shell rejoices in the following 

 variety of titles : — 



Scrobicularia piperata [Gmelin sjp.). 



Trigonella plana [Da Costa). 



Mactra Listeri (Aud.). 



Mya Hispanica [Chemnitz). 



Yenus borealis [Pennant). 



Lutraria compressa [Lamarck). 



Arenaria plana [Megerle). 

 As regards specific names, the earliest ought certainly to be 

 adopted, with^ however, the following exceptions : — 



1. MS. names ; which are admitted by courtesy. 



2. Names given by writers antecedent to Linneeus. 



3. Names unaccompanied by a description or figure. 



4. Barbarisms ; or names involving error or absurdity, f 

 It is also very desirable that names having a general (Euro- 

 pean) acceptation should not be changed on the discovery of 

 earlier names in obscure publications. 



emblem of eternity— the serpent holding its tail in its mouth. The following diagram 

 is offered as an improved circular system : — 



[Fishes.] 

 Di-branchiata. 



Nucleo- . . Tetra- 

 Opistho- \ / Proso- 



Aporo- "^ Pulmo- 



Pallio- Lamelli- 



Hetero-branchiata. 

 [Zoophytes.] 

 * In Pfeiffe^'s Monograph of, the Helicidce, a family containing seventeen genera, 

 no less than 330 generic si/nonyms are enumerated ; to this list Dr. Albers, of Berlin, 

 has added another hundred of his ovra invention ! 



t This subject was investigated and reported upon by a committee of the Britisli 

 Association in 1842, 



