82 Revieivs — Dollds Binosauria of Bernissart. 



which various authors have defined the genera which are allied 

 to Iguanodon ; and on an estimate of the characters by which the 

 three known species, at present referred to Iguanodon, have been 

 characterized. Those species cannot, however, be completely com- 

 pared. The Iguanodon Mantelli has five sacral vertebra, and the 

 pre-acetabular part of its ilium is half the length of the bone. 

 Iguanodon Prestwichi has four sacral vertebree. Iguanodon Seelyi 

 has the ilium three times as long as its pre-acetabular portion ; but 

 its sacrum is not at present known. 



The author then goes on to show that the differences of propor- 

 tion between the principal bones of the fore and hind limbs in the 

 type specimen of Iguanodon Mantelli, and the smaller Iguanodon in 

 Brussels, amount to only a small percentage ; and compares the 

 type slab from the Lower Greensand of Maidstone with the Brussels 

 animal, with the following results : — 



Ilium, Femur. Tibia. Scapula. Humerus. Eadius. 

 Maidstone spm.... 0-75 0-81 0-75 0-72 0-47 0-45 

 Brussels spm. ... 0-71 0-71 0-67 0-62 0-43 0-37 

 showing that the Brussels animal is somewhat smaller, and that 

 the proportions of the fore and hind limb are not quite the same. 

 He then discusses the nomenclature of the larger type, and recog- 

 nizes its extremely close correspondence with the Iguanodon Seelyi 

 of Hulke, with which he would have had apparently no hesitation in 

 identifying it, but for the following remarkable passage, in which 

 Mr. Hulke states "I had long possessed evidence that Iguanodon 

 had a scuted hide ; but until the acquisition of these remains, such 

 evidence was very fragmentary. In cutting away the rock from the 

 larger bones of the hind limb, I found beneath it a layer of bony 

 tissue, separated from the endoskeleton by a deeper layer of rock, 

 enclosing much black carbonaceous matter. From its position with 

 reference to the endoskeleton, it was obvious that the outer layer of 

 bony tissue was exoskeletal — was in short a dermal mail." Mr. 

 Hulke further describes these bones as irregularly polygonal, with 

 a surface slightly pitted, some of them 2cm. thick and 7cm. in 

 diameter. M. Dollo finds evidence of the integument, but no trace 

 of bony armour, which he thinks should separate the species, but 

 maintains that if the large Brussels form is identical with the 

 Iguanodon Seelyi, priority must be claimed for Boulanger's name, 

 Iguanodon Bernissartensis. 



The author follows Marsh in placing Iguanodon in the Ornitho- 

 poda, but makes a criticism, which was valuable at the time, in 

 opposition to the view that clavicles formed a characteristic of the 

 group, urging that the bones which were thus identified by Marsh 

 are elements in the sternum. The note concludes with a definition 

 of the order Ornithopoda, and its families, a definition of Iguanodon, 

 and definitions of the three species. 



There is no doubt that M. Dollo is substantially in harmony with 

 Mr. Hulke in his views concerning the classification of these 

 Dinosaurs. But I ventured, when the description of the Iguanodon 

 PrestioicM was read before the Geological Society in 1880 to 

 express an opinion that the characters of the sacrum, of the 



