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ECHINOIDEA EXOCYCLICA. 



Echinodermata, and twenty years' experience has only afforded additional evidence of 

 their truth. 



" Many of the readers of this Monograph will probably be surprised to find some old 

 generic names reproduced which have been long superseded by those of modern writers ; 

 but a sense of justice to such authors as Van Phelsum, Breynius, Klein, and Leske has 

 led me to consult their original works and restore the genera first described and figured 

 by them, but omitted from the treatises of later authors on the same subject. 



" In the nomenclature of the Echinodermata, had I merely gone back to the time of 

 Linnaeus, as suggested by the Committee of the British Association in their Report made 

 in 1842. I must necessarily have excluded the important work by Breynius, 1 in which, 

 for the first time, were proposed seven well-described and accurately figured genera of 

 Echinoidea, which, by some strange oversight, were not adopted by his contemporaries, 

 although they have reappeared under new names in the works of later authors. On the 

 principle of priority, therefore, I have restored the original genera so clearly defined by 

 Breynius, even although it may occasion a temporary inconvenience in the names of some 

 well-known forms of Urchins. 



" In every case where practicable the name of the author who either first recorded, 

 described, or figured the species follows the specific name of the object without the 

 addition of ' Sp.' adopted by some authors. By this mode justice is done to the original 

 author and confusion avoided. The modern practice of inventing new generic terms and 

 appending to the old specific name that of the individual who has merely changed a 

 word but discovered nothing cannot be sufficiently discountenanced, as it increases the 

 confusion arising from an overloaded synonymy, and thereby retards the real progress of 

 the natural-history sciences." 2 



The first author who described systematically and figured accurately many typical 

 forms of Echinidce was undoubtedly Breynius, 3 in his ( Schediasma de Echinis ;' he takes 

 the general form of the test and relative position of the vent as the basis of his 

 methodical arrangement, in which he groups the whole order into the seven following 

 genera. 



I. Genus — Echinometra, Breynius, 1732. 



Shell more or less globular, the mouth and vent occupying the two poles. This 

 genus was retained by Gaultieri, 1742 ; by Seba, 1758, and by Van Phelsum, 1770 ; but it 



1 De Echinis et Echinitis, sive methodica Echinorum distributione, Schediasma. Gedani, 1/32. 



2 'Monograph on the British Fossil Echinodermata oFthe Oolitic Formation,' p. vii, Pal. Soc. vol. for 

 1855. 



3 Joannis Phillippi Breynii dissertatio physica de Polythalamiis — tandemque Schediasma de Echinis 

 methodice disponendis cum figuris. Gedani, 1732. 



