440 Scientific Intelligence. 



Crocodilians and LacertEe. Other large vertebra? found with bones of 

 the extremities, ribs, &c, of the Iguanodon, and referred by Professor 

 Owen to the genus Cetiosaurus^ are regarded, in consequence of the 

 peculiar structure of the neural arch, as belonging to the posterior dor- 

 sal or lumbar vertebrae of the former colossal reptile. Certain angu- 

 lar caudal vertebrae, also previously assigned to a species of Cetiosau- 

 rus, are considered by the authors as referable to the middle and distal 

 regions of the tail of the enormous saurian, with whose bones of the 

 extremities they are constantly found associated. 



The Sacrum. — Several examples belonging to individuals of vari- 

 ous sizes and age, are described. The sacrum is shown to consist of 

 six anchylosed vertebrae, and not of Jive only, as stated by Professor 

 Owen ; and the typical specimen described by the latter eminent anato- 

 mist, was exhibited by Dr. Mantell in proof of this assertion. The 

 anterior vertebra, and the two posterior vertebra? are much longer and 

 stronger than the three intermediate elements that occupy the centre of 

 the sacral arch. ; 



Pectoral arch. — A perfect scapula or omoplate of the crocodilian 

 type recently discovered in Tilgate Forest, and which corresponds with 

 a coracoid bone formerly referred by the author to the Iguanodon, 

 (Philos. Trans., 1841), is proved to belong to that reptile, from the re- 

 mains of two similar scapulae in the Maidstone specimen in the British 

 Museum.* As the clavicals were already known, the essential ele- 

 ments of the pectoral arch of the Iguanodon are doW for the first time 

 ascertained ; and the author gives a restored figure of this important 

 part of the skeleton. 



The Humerus or arm-bone. — A humerus three feet long, found in the 

 Isle of Wight, has been ascertained by Dr. Mantell to belong to the 

 Iguanodon, from its entire correspondence with a bone in the Maidstone 

 fossil, previously undetermined. This last bone, from its disparity in 

 size in comparison with the femur — being one-third shorter — was for- 

 merly assigned to the fore-arm, but the fossil from the Isle of Wight 

 enabled the author to ascertain its true place in the skeleton. It now 

 appears that in the Iguanodon, as in many fossil and recent reptiles, 

 the anterior extremities were shorter and less bulky than the posterior. 

 The radius and ulna are still unknown, but the author conceives that 

 certain imperfect bones in his former collection (now in the British 

 Museum), are those of the fore-arm. 



Hinder extremities.— The colossal magnitude of the Iguanodon is 

 strikingly shown by some thigh and leg-bones recently discovered in 

 ^the Isle of Wight. A femur or thigh bone is four feet eight inches 

 •long ; and a tibia or leg-bone four feet Jong. 



Dermal scutes and Spines.— The author figures and describes several 

 dermal scutes and spines, and states that a microscopical examination 

 of the large angular bones of the Hytaosaurusf supposed by him to be 

 ossified dermal spines, but which Professor Owen regarded as more 

 probably referable to the abdominal ribs, proves the correctness of his 

 own opinion, for their structure is identical with that of the indisputa- 

 ble dermal scutes. 



* Figured in Dr. Mantell's Wonders of Geology. 

 f See a figure in Dr. Mantell's Medals of Creation, 



