h. govier seeley on maitisattrtts gakdneri. 547 



Discussion. 



Mr. Gwyn Jeffreys, with reference to the habits of the Walrus, 

 stated, on the authority of Prof. Torell, that it feeds on the Mya 

 truncata, a mollusk which lies buried in gravelly mud. In order 

 to get this raoHusk, it has to grub up the mud with its tusks, and 

 takes up the mud and pebbles along with the Mya into its mouth. 



Mr. J. S. Gardner said he regretted that all the vertebrae of 

 the Saurian had not been brought for exhibition, as the smallest of 

 the cervical vertebrae would have shown more plainly the great dis- 

 proportion existing between them and the vertebrae of the trunk, 

 and thus have given a better idea of the great length of the neck. 

 He remarked that the bones, when in situ, were very fragmentary, 

 and some had oysters adhering to them, showing that they had been 

 long exposed before fossilization. He stated that pebbles were 

 exceedingly rare in the Gault, and suggested that the reptile may 

 have been stranded, and that the pebbles became entangled in its 

 carcass. 



Mr. J. W. Htjlke believed, with the author, that the remains 

 indicated a new species of larger size than any previously found in 

 this country. In the long, tapering neck, the lateral position of the 

 articular head of the limb-bones, and the form and structure of the 

 cervical ribs, he noticed resemblances to the large Kimmeridge 

 Plesiosaurus (P. Manselli) which he brought under the notice of the 

 Society several years ago, and which he thought would fall into 

 Prof. Seeley's subgenus Murcenosaurus. With regard to the pebbles, 

 he suggested that the animal may not have swallowed them as an 

 aid to the comminution of food in its stomach, but that they were 

 introduced in the stomachs of fish which it had swallowed. The 

 flesh and, subsequently, the bones of these would be digested and 

 absorbed, whilst the indigestible stones, if the stomach of the 

 Plesiosaurus was like that of Crocodiles, would be unable to pass 

 through the small pyloric opening into the intestine, and must per- 

 manently remain in the stomach. 



The Author briefly replied. 



