200 PETRIFACTIONS AND THEIR TEACHINGS. CHAP. III. 



ferruginous sands of New Jersey, in the United States. In 

 1830, my lamented friend, the late Dr. Morton of Phila- 

 delphia, (whose early death is so much to be deplored,) sent 

 me specimens and casts of teeth of Mosasaurus, which 

 agreed in every respect with those from the Netherlands ; 

 teeth of this kind are figured in Dr. Morton's " Synopsis 

 of the Organic Kemains of the United States :" Philadelphia, 

 1834. Of late years, vertebrae and other bones of the 

 same genus have been found in these deposits ; some of 

 which, collected by Prof. Rogers, are figured and described 

 in the Quarterly Journal of the Geological Society of 

 London. 



POLYPTYCHODON. Wall-case B. In a frame on the top 

 of this Case there is a group of bones, some of which are 

 nearly entire, others mere fragments, imbedded in plaster, and 

 belonging to a large marine reptile ; they are from the green- 

 sand strata near Hythe in Kent, and were collected and pre- 

 sented to the Museum by H. B. Mackeson, Esq. No part of 

 the cranium or jaws has been discovered ; but in. the same 

 deposits, as well as in the white chalk, very large conical 

 longitudinally ridged teeth frequently occur ; these have 

 received the name of Polyptychodon. Prof. Owen, assuming 

 that the teeth he has thus designated belong to the same 

 species of reptile as the bones found in the same strata, has 

 described the above isolated parts of the skeleton under the 

 same name. 



These consist of fragments of bones referred to the cora- 

 coid, ilium, ischium, and pubis ; and portions of the humerus, 

 part of a femur, tibia, and fibula, and several metatarsal 

 bones. Of these, the thigh-bone, of which above two feet of 

 the shaft remains, at once separates the reptile to which it 

 belonged, from the Iguanodon and other gigantic saurians 

 whose relics are occasionally found in the same formation, 

 for it has no medullary cavity, its centre being occupied 

 by a coarse cancellated structure, as in the cetaceans ; this 

 fragment is fifteen inches in circumference. The metatarsal 

 bones are the most perfect of these remains ; the longest 

 was two feet in length, and four inches in transverse diameter 

 in the middle. 



Neither teeth nor vertebrae have been found, and the pro- 

 visional name "Polyptychodon" simply indicates that the 



