546 H. GOVIEft SEELEY 0J5T MATJISAFKTJS GAEDNERI. 



distally it becomes compressed and is apparently to some extent 

 crushed from above downward, though an uncompressed fragment 

 is 3 inches in thickness. The internal aspect is concave in length, 

 and the external aspect convex. Both lateral margins appear to 

 have been moderate^ concave ; but the anterior margin is imperfect 

 distally ; if preserved it would probably have made the bone 

 9 \ inches wide. The distal articular margin for the bones of the 

 forearm is nearly straight ; and the surface for the radius does not 

 make an angle with the surface for the ulna. The bone was un- 

 usually massive, and relatively to the vertebrae is much longer and 

 broader than in Dr. Hector's Mauisaurus Haastii. 



The femur is imperfect at both ends. The fragment preserved is 

 13 inches long. The proximal end of the bone is nearly cylindrical 

 and about 4 inches in diameter. The anterior margin of the bone 

 is very slightly concave, so as to be nearly straight ; the posterior 

 outline is deeply concave. 



The phalanges appear to have been compressed from above down- 

 wards and unusually long. Only one has been found (PI. XXIII. 

 fig. 6) imperfectly preserved ; it is about 4| inches long, 1| inch 

 wide where most constricted in the middle, and was probably 2 inches 

 wide at the extremities. 



In the lower dorsal region of the animal about a peck of ovate 

 and rounded pebbles occurred, varying in size from a diameter of a 

 quarter of an inch to a length of nearly two inches. They are 

 chiefly of opaque milky quartz. Several are of black metamorphosed 

 slate, and a few of altered fine-grained sandstone and hornstone, 

 some of the pebbles showing a veined character, such as might be 

 derived from the neighbouring Palaeozoic rocks of the North of 

 Prance. Pebbles being of such rare occurrence in the Gault, it 

 would seem natural to account for these associated stones on the 

 hypothesis that they were swallowed by the animal with food, as is 

 the case with certain living reptiles and birds. If this view should 

 be held admissible, it would suggest that as the teeth were too small 

 for any thing but prehension, a structure analogous to a gizzard, or 

 the stomach of an edentate, may have used these pebbles to assist in 

 breaking up or crushing the food on which this Saurian lived. 



EXPLANATION OF PLATE XXIII. 



Bones of Mauisaurus Gardneri from the Gault of Folkestone. 

 The figures of the vertebras are half the natural size. 



Fig. 1. Prehensile tooth, of the plesiosaurian type, a, crown ; b, fang. Nat. size. 



2. Middle cervical vertebra, side view. 



3. Late cervical vertebra, with the pedicle (t) for the ribs rising above the 



sides of the centrum. 



4. Pectoral vertebra with the pedicle for the rib formed partly by the 



centrum and partly by the neural arch. 



5. Dorsal vertebra, showing the broken transverse processes (t), and base 



of the neural spine. In the British Museum. 



6. Phalange, imperfect ; natural size. 



