96 



THE AMERK A.X \.l i rh'.l IJST. [X'oi,. XXXVniI. 



False Principles of Classification. 

 Superficial Resemblances.— In Brogniart's system of 1799 the 

 Lacertilia and Crocodilia are wrongly united on limb structure 

 as (II) Saurii, as distinguished from (III) Ophidii, and (I) 

 Chelonii. 



The similar scaly covering led Latreille (1820) to rightly 

 unite the Ophidia and Lacertilia as Squamosa ; previously Oppel 

 (181 1) grouped the Lacertilia and Ophidia as Squamata ; this, 

 however, is the single instance in which epidermal resemblance 

 happens to coincide with underlying fundamental characters. 



As instances of errors based upon epidermal characters, we 

 may cite the union of the Testudinata and Crocodilia by Klein 

 as Cataphracta ; or the union of the same animals by Merrem 

 as Loricata. 



Resemblances in Single External Organs.— So able a palae- 

 ontologist as von Meyer (1830) attempted to classify the 

 reptiles by resemblances in foot structure. He thus divided the 

 Saurii, or limbed reptiles into (i) Dactylepodes, including Lacer- 

 tilia and Crocodilia ; (2) Nexipodes, including the Ichthyosauria 

 and Sauropterygia {Plesiosaurus, Xothosanrns) ; (3) Pachypodes, 

 mcludmg the Iguanodontia and Megalosauria ; (4) Pterodactylii, 

 mcluding the Pterosaurs -a false system. 



Classification of Analogous Adaptations.— De BlainviUe (1835) 

 united the Ichthyosauria and Sauropterygia as Enaliosaurii, or 

 sea lizards. Owen (1839) adopted the order Enaliosauria as 

 embracing the Ichthyopterygia (1859) and Sauropterygia (1859), 

 but remarked that these animals - do not form a strictly natural 

 Rroup." 



Classification by single Internal C/mracters.—This method was 

 especially characteristic of Cope. In 1869 he defined the Arch- 

 osauria as differing from the Monimostylica of Miiller only by 

 the exclusion of the order Testudinata; he observed that close 

 sutural attachment of the quadrate bone "was the important 



feature which characterizes 



the order " ; by this featur 



united the Sauropterygia (Nothosaurus, which was selected as a 

 yi>e) the Crocodilia, the Thecodontia (suborder of Dinosauria), 

 the Dmosauna, the Anomodontia, and the Rhynchocephalia ; a 



otally 



transitory grouping, because based 



