305 



Its geological habitat is the Kimmeridge clay 

 near Weymouth, and in the Headington quarries 

 near Oxford. 

 JMegalosaurus.* 



An animal, apparently approaching the monitor in its 

 mode of dentition, &c. not yet described. It is found in 

 the calcareous slate of Stonesfield, subordinate to the upper 

 part of the lower or great oolitic series, including the forest 

 marble, 6:c. Drawings have been made of the most essen- 

 tial parts of the animal, now in the Museum at Oxford ; 

 and it is hoped a description may shortly be given to the 

 public. The animal must, in some instances, have attained 

 the length of forty feet, and stood eight feet high. 



Mr. Con^^beare states, that he has never seen the bone which he 

 had called, in the ichthyosaurus, the furcula or sternal arch, which 

 he thinks it is most probable, from the form of the scapula, must 

 have existed in this animal also. 



The bones of the anterior extremity, the flat clavicles similar to 

 those of the ichthyosaurus, the scapula and humerus, were foimd, 

 though loose and detached. Two bones were also found to which 

 were assigned the office of radius and ulna, their articulating sur- 

 faces agreeing at one end with those of the humerus, and, at the 

 other, with those of the paddle. 



The three first paddle or carpal bones have a general resemblance 

 to the phalanges of reptiles, but are more flattened. The series of 

 small bones fonning the paddle was very numerous, approaching, 

 in this respect, to the stiucture of the analogous part in the ichthyo- 

 saurus, with a series of round bones like those which form the 

 external bones of the ichthyosaurian paddle. 



Thus, therefore, Mr. Conybeare observes, a general similarity of 

 organization between this important member in the plesiosaurus and 

 ichthyosaurus appears to be established ; whilst, on the other hand, 

 a comparison with the paddles of the sea-turtle will exhibit such 

 fresh analogies as to indicate that, in respect of the various forms 

 of the animal extremities, the plesiosaurus holds, as it were, a middle 

 place between it and the ichthyosaurus. 



* MeyCiXoo", great, and S^U^Off", a lizard. 



R r. 



