it PRESIDENT'S ADDRESS. 



of the present day. In the extinct Order of Sauropterygia, of 

 which, perhaps, the Plesiosaurus is the best known, the body was 

 without an exo-skeleton, while the neck was more or less 

 elongated and the tail short. The teeth, which are implanted 

 in distinct sockets, have curved crowns. The ischium resembles 

 those of Amphibia, which have a long symphysis. The limbs of 

 the earlier generalized forms are adapted for progression on 

 land, while in the specialised types they are modified into 

 paddles. The limbs are readily distinguished from those of the 

 Ichthyopterygia by the relatively longer humerus and femur. 



Plesiosauridse This group was adapted for a purely aquatic 

 life, and probably frequented sea-coasts and estuaries. Being an 

 air-breather it had to come to the surface occasionally for 

 respiration. The genus Plesiosaurus is now restricted exclusively 

 to the upper Trias (Rhaetic) and the Lias. Cimoliosaurus, from 

 the Inferior Oolite to Cretaceous beds, is characterised by the 

 elongation of the centra, with flat faces and enormously high 

 neural spines. 



Reptiles in the passage of time have suffered more severely 

 than any other class of the vertebrata. Of the ten original 

 Orders proposed by Baur, only four are now existing, Chelonia, 

 Rhynchocephalia, Squamata, and Crocodilia. There is some doubt 

 as to their earliest known appearance. Protosauria and many 

 of the European Anomodontia have been undoubtedly found in 

 the Permian. All the ten Orders, with the exception of the 

 Ornithosauria and Squamata, occur in the Trias. The former 

 appeared in the succeeding Lias, but no traces of Squamata have 

 as yet been found in any bed earlier than the Upper Jurassic ; 

 these reached their fullest development in that and Cretaceous 

 epochs. 



Anomodontia The most remarkable feature of this Order 

 is its resemblance to the extinct Labyrinthodont Amphibians 

 on the one hand, and to the living Monotreme mammals 

 on the other. The vertebrae are amphiccelous, and in some cases 

 have notochordal centra. The Order is supposed to be confined 

 to the Permian and Trias. The sacrum differs from that of all 



