ON THE NAMES PLESIOSAURIA AND SAUROPTERYGIA. 221 



13. On the Use of the Ncanies Plesiosanria and Sauropterijgia. 

 Bj a. A. BOULENGER, F.H.S., F.Z.S. 



[Received October 6, 1917 : Read November 6, 1917.1 



Index. 

 Systematic : . Pnare 



On i\w \\a,\\\Q?, Flesiosauria n\\i\. Saurojpterygia 221 



I wish to point out the misappHcation, or rather inverted 

 appUcation, of the names Plesiosauria and Saurajiterygia by some 

 of the most recent writers on the classification of fossil Reptiles. 



The order Plesiosauria was so named, and properly defined, by 

 de Blainville in 1835 * ; the genus Plesiosaurus was then its only 

 i-epresentative. 



When, in 18.39, Owen f a,ccepted the name Enaliosauria 

 (Conybeare, 1821) for the marine Reptiles known as Plesiosaurs 

 and Iclithyosaurs, which were associated in one order, he desig- 

 nated the former as Plesiosauri and the latter as Ichthyosauri. 

 After the relationship of the Nothosa,urs to the Plesiosaurs had 

 been recognised by Hermann von Meyer, they were placed 

 together as Plesiosauri by Quenstedt in 1852 J. 



Plesiosauria (1835-1852) is the earliest name for the order in 

 question, it is open to no objection, and it should therefore be 

 used, as it has been by Huxley, Gegenbaur, Cope, Baur, Hay, 

 and myself. 



In 1859, Owen§, dropping the artificial group Enaliosauria, 

 proposed to call Sauropterygia and Iclithyopterygia the two orders 

 on which he had already bestowed names which there was no 

 need to change. The Saui'opteiygia were defined as long-necked 

 marine Reptiles with fin-like limbs with not inore than five 

 digits. Owen insisted on the character of the limbs as distinctive 

 of the order and, although accepting the proposition that the 

 ISTothosaurs should be included, remai'ked, rather inconsistently : — 

 " I continue, as in my former Report of 1841, to i-egard the fin- 

 like modification of the limbs as a better ordinal character than 

 the number of vertebrae in any particular region of the spine 



The Plesiosmbrus, with its very numerous cervical 



vertebra?, sometimes thirty in number, may be I'egarded as the 

 type of the Sauropterygia or pentadactyle sea-lizards." 



It is therefore perfectly clear, and beyond discussion, that the 



* Ann Mas. Paris (3) iv. p. 241. — Reference to this important contribution to 

 the classification of Rei)tiles has unfortunately bei n omitted from 0. P. IIa3''s most 

 useful biblioojraphy, 15ull. U.S. Geol. Surv. no. 179, 1902. 



t Rep. Brit. Assoc. 18.39, p. 45; also 1841, p. 60. 



J Handbuch der Petrpfaktenl<nnde, p. 130. 



§ llep. Brit Assoc. 1859, p. 1,39. 



