240 BRITISH FOSSIL REPTILES. 



intelligiljly defined when the name is given, it cannot be recognised by others, and the 

 signification of the name is consequently lost. Two things are necessary before a 

 Zoological term can acquire any authority, viz. definition and puhlication. Definition 

 properly implies a distinct exposition of essential characters, and in all cases we 

 conceive this to be indispensable.* 



Now with regard to the Pterodadylus giganteus, I always understood Mr. Bowerbank 

 to apply the term to the species to which the long wing-bone first described by 

 me might appertain, under the circumstances of its being proved to belong to a 

 Pterodactyle, and my belief in this definition of his species was confirmed by the fact 

 of his subsequently figuring the two similar and equal-sized bones in the ' Quarterly 

 Journal of the Geological Society,' Vol. IV, pi. 2, fig. I, (Proceedings of the Society 

 for June 9th, 1847,) as the "radius and ulna oi Pterodadylus giganteusr So far as a 

 species can be intelligibly defined by figures, that to which the term giganteus was, in 

 1845, provisional^, and in 1847 absolutely applied, seemed to be clearly enough 

 pointed out by the Plate 2, in the Work above cited. But with the large bones 

 appropriately designated by the term giganteus, some part of a smaller Pterodadgle, 

 including the portions of jaws first announcing the genus in the Chalk, had been 

 associated under the same name. Supposing those bones to have belonged to a young 

 individual of the Pterodactylas giganteus, no diflBculty or confusion would arise. After 

 instituting, however, a rigid comparison of these specimens, I was compelled to arrive 

 at the conclusion that the parts figured by Mr. Bowerbank, in Plate I, figs. 1 and 2, of 

 Vol. II of the ' Quarterly Geological Journal,' and the parts figured in Plate 2, figs. 

 1 a and b of Vol. IV, of the same Journal, both assigned by Mr. Bowerbank to the 

 Pterodactyhs giganteus, belonged to two distinct species. The portions of the scapula 

 and coracoidof the Pterodactyle (PL l,fig. 2, vol. ii, op. cit.) indicates, by its complete 

 anchylosis, that it has not been part of a young individual of the species to which the 

 large antibrachial bones (PI. 2, fig. 1, a and b, vol. iv, op. cit.) belonged, although it might 

 well appertain to the species to which the jaws (PL 1, fig. 1, vol. ii,) belonged. Two species 

 of Pterodactyle were plainly indicated, as I have shown in the Work by my lamented 

 friend, Mr. Dixon, ' On the Tertiary and Cretaceous Deposits of Sussex,' 4to, p. 402. 

 The same name could not be retained for both, and it was in obedience to this necessity, 

 and not with any idea of detracting an iota from the merit of Mr. Bowerbank's original 

 announcement of the existence of a Pterodactyle in the Chalk, that I proposed the name 

 of conirostris for the smaller species, then for the first time distinctly defined and dis- 

 tinguished from the larger remains, to which the name giganteus had also been given 

 by Mr. Bowerbank. I proposed the name, moreover, provisionally, and with sub- 

 mission to the Committee for the Reform of Zoological Nomenclature, according to 

 whose rules I believed myself to have been guided. 



* See their 'Report,' Trans, of the British Association for 1842, 113. 



