8 TORTOISE. 



&c. according to the different periods of their 

 growth. 



The specific characters given by Linnsus, in 

 the Systenia Naturae, are proved, from later ob- 

 servations, to be entirely insufficient for the pur- 

 pose of accurate distinction ; and the same must 

 be said of those in the Gmelinian edition of that 

 work. The descriptions of the Count de Cepede, in 

 his History of Oviparous Quadrupeds, have by no 

 means tended to dispel the general obscurity, but 

 have in some instances rather increased it; and 

 throughout almost all authors will be found to 

 prevail a confusion of synonyms and references. 

 Mr. Schneider, Mr. Schoepff, and some others, 

 have lately endeavoured to elucidate this difficult 

 genus, and have contributed to a somewhat clearer 

 knowledge of the species and varieties. One ob- 

 servation of Mr. Schoepffs is of peculiar import- 

 ance, and may save zoological students a consi- 

 derable degree of unnecessary trouble, viz. that 

 the apparent number of claws or projecting ex- 

 tremities on the feet of the marine tortoises or 

 turtles, appears to be no certain criterion of the 

 species ; but, on the contrary, is found to vary in 

 such a manner as to contradict the Linnaean spe- 

 cific characters. Thus, on collating a number of 

 specimens of the T. Mydas, or common green 

 Turtle, some will be found with only a single 

 claw on each of the feet ; others, with two, or 

 even three ; and others with two on the fore feet, 

 and one on the hind. It also appears, from the 

 observations of Cetti and others, that a similar 



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