48 MANUAL OF THE MOLLTJSCA. 



NOMENCLATURE. 



The practice of using two names — generic and specific — ^for 

 eacli 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 opprobrium in all branches 

 of natural history.* 



One very common estuary shell rejoices in the following 

 Tariety of titles : — 



Scrobicularia piperata [Gmelin sp.), 



Trigonella plana [Da Costa). 



Mactra Listeri [Auct.). 



Mya Hispanica {Chemnitz). 



Venus 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 Linnaeus. 



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 — tlie serpent holding its tail in its mouth. The following diagram 

 is offered as an improved circular system : — 



[Fishes.] 

 Di-branchiata. 



Nucleo- V ., Tetra- 



Opistho- ^ 



<,^^^ Proso- 



Aporo- 



^1 Puhno- 



Pallio- 



Lamelli- 



Hetero-branchiata. 

 [Zoophytes.] 

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

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

 has added another hundred of his ovm invention ! 



t This subject vraa investigated and reported upon by a committee of the British 

 Association in 1842. 



