CLASSIFICATION OF THE BRACHIOPODA. 43 



sequent researches alone will remove ; and because such have occurred in the infancy of 

 the science, ought we to cancel all that fifty years of arduous researches has brought to 

 light, and retrace our steps, as some would wish, to the period of Linnaeus? No one 

 has, as yet, nor will any one for some years to come, be able to produce a complete and 

 satisfactory classification of the numberless species and varieties composing the order; 

 because, to hope to arrive at such a condition, it is absolutely necessary to be thoroughly 

 acquainted with the interior arrangement and other characters of all the species one has 

 to classify, and I am sorry to say we are still very far from having attained so desirable 

 a state; all we can do, therefore, in the mean time, is to assemble conscientious obser- 

 vations, and gradually improve the general views in circulation at the time being. 



Soon after the publication of Cuvier's discoveries, several new and excellent genera 

 were from time to time introduced by Sowerby, Lamarck, Defrance, Fischer de Waldheim, 

 Dalman, and others, which, with their dates and synonyms, will be found recorded 

 under the heads of the different genera. 



In 1818, Lamarck regarded the Brachiopods as forming the greater part of his 8d 

 section of the Conchiferes Monomy aires : — 



1. Les Rudistes. 1, Spherulite; 2, Radiolite; 3, Calceole; 4, Birostrite; 5, Discine; 



6, Cranie. 



2. The Brachiopoda. 1, Orbicule; 2, Terebratule; 3, Lingule} 



In 1824, M. de Blainville placed at the head of his Acephalophores an order, 

 which he named Palliobranchiata, as a substitute of Brachiopoda.^ He divides this order 

 as follows : — 



1. Symmetrical Shells, Lingula, Terebratula, Thecidea, Strophomena, Plagiostoma, 

 Dianchora, and Podopsis. 



2. Unstmmetrical Shells, Orbicula and Crania. The genus Calceola he places in 



detect the relations between structure and function. More definite principles of classification may here- 

 after be discovered, and meantime all that we can do is to arrange our systems according to sound reason, 

 and without theoretical pi-epossession. By care and judgment much may be done to give greater regularity 

 and exactness to our methods of classification, either by introducing new groups where the importance 

 of certain characters requires it, or by rejecting such as have been proposed by others on insufficient 

 grounds. At the present day, many authors are in the habit of founding what they term new Genera upon 

 the most trifling characters, and thus drowning knowledge beneath a deluge of names. ... In the 

 sub-dividing of larger groups into genera, even in the strictest conformity with the natural method, there 

 is evidently no other rule but convenience to determine how far this process shall be carried. 

 Nature affords us no other test of the just limits of a genus (or indeed of any other group) than the 

 estimate of its value which a competent and judicious naturalist may form. The boundaries of genera will 

 therefore always be liable to fluctuate. . . . The only remedy for this excessive multiplication of genera 

 is for subsequent authors, who think such genera too trivial, not to adopt them, but to adopt the old genua 

 in which they were formerly included." 



1 Hist, des Animaux sans Vertcbres. 



2 Die. des Sciences Nat,, t. xxxii, p. 298 ; and Manuel Malac, &c. 



