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NATURE 



{Sept. 6, 1883 



of Prof. Giard of Lisle, was appointed about two years 

 ago as assistant naturalist to the Museum for the purpose 

 of investigating the lguanodons. He is full of enthusiasm, 

 as an ardent naturalist such as he is well may be with 

 the whole Bernissart material before him. He works 

 incessantly at the subject, but he does not see prospect of 

 publishing the complete monograph on the lguanodons 

 which he intends to issue sooner than five or six years 

 hence- He will not of course venture to prepare the 

 final monograph until he has the whole of the material 

 concerned before him. He estimates the number of in- 

 dividuals represented by skeletons in the find as twenty- 

 three, two of which belong to the species /. Mantelli, and 

 twenty-one to I. Bernissartensis. Of these twenty- 

 three, fifteen have as yet been chiselled out of the blocks 

 ready for study, eight remain as yet to be worked at, and 

 although four or five skilled artificers are constantly at 

 work on the specimens progress is necessarily slow. The 

 cellars full of the material present an astonishing appear- 

 ance. < )ne first enters an extensive, dimly lighted vault, 

 the whole floor of which is covered with large blocks, 

 many still in the condition in \vhi:h they came from the 

 mine, of all shapes, and lying in all sorts of positions, so 

 closely placed that it is very difficult to get about amongst 

 them to inspect them more closely. All contain huge 

 bones, forming parts of the skeletons of the lguanodons, 

 often covered up by the protective plaster, but with here a 

 hand, there a foot, elsewhere a range of vertebra; showing 

 out. In an adjoining cellar is the workshop where various 

 blocks are seen in the process of the removal of the 

 matrix, whilst at one end, hung up to stout beams, are the 

 results of the operation, a vast collection of all imaginable 

 segments of the skeletons of Iguano-lons suspended in 

 the air, and suggesting the idea of joints of meat in the 

 shop of some Brobdingnagian butcher. 



As before mentioned, one of the skeletons of Iguan- 

 odon Bernissartensis has been restored and mounted by 

 Mr. J. F. de Pauw. The specimen is almost entirely 

 complete, only a (e\v phalanges and one or two minor de- 

 tails having required to be reconstructed. It was not found 

 possible to detach the bones from one another before 

 mounting them. They are mostly mounted still joined 

 to one another in sections by the matrix as removed from 

 the mine. It was therefore impossible to give to the 

 skeleton as natural a pose as might have been wished, 

 and as M. de Pauw hopes to accomplish with some of 

 the other specimens more favourably preserved ; but 

 taking all circumstances into consideration the present 

 result of his work is a marvellous success, in which it 

 needs a very trained eye indeed to detect anything amiss. 

 The grand skeleton is set up in a huge glass chamber in 

 the court of the Museum. As it stands in the natural 

 att tude of progression of the animal on land, erect on 

 its hind limbs, the top of its snout is at an elevation of a 

 few inches over 14 feet from the ground, whilst from the 

 tip of the tail outstretched behind to a point immediately 

 beneath the tip of the snout the skeleton covers a horizon- 

 tal space of floor about 23 feet in length. 



As soon as M. Dollo set to work on the details of the 

 structure of the lguanodons, he very widely determined 

 to publish at once a series of preliminary notes giving the 

 main results of his investigations. Four of these have 

 now been issued as enumerated at the commencement of 

 the present article, and from the third memoir is copied 

 the figure of the entire skeleton, here reproduced some- 

 what reduced in size. From these notices is taken the 

 information which follows. 



M. Dollo's first care was to determine the species of 

 the lguanodons with which he has to deal. It will be 

 remembered that his predecessor, M. G. A. Boulenger, 

 who left Brussels to join the zoological staff of the 

 British Museum, recognised among the remains a new 

 species of Iguanodon, characterised by having six sacral 

 vertebra; instead of five as in /. Mantelli and four in /. 



Prestwichii. Professor P. J. van Beneden, however, in 

 the absence of further detailed information, held the 

 opinion that the number of the sacral vertebra? could not 

 be regarded as a specific character amongst lguanodons, 

 and that our knowledge then on the matter could only be 

 expressed by stating that in the Dinosauria the sacral 

 vertebra; vary in number from four to six. He did not 

 therefore accept M. Boulenger's determination as valid, 

 but regarded the whole of the specimens as belonging 

 to /. Mantelli, M. Dollo, however, confirms M. Bou- 

 lenger's con lusions; he finds that there are two forms of 

 lguanodons present, a large one and a small one, and 

 the small one is certainly not the young of the large one. 

 It is a remarkable fact that there are no young examples 

 amongst the whole of the Bernissart Dinosaurians, as is 

 shown by the facts that in all of them the cranial 

 sutures are obliterated, and the sternal bones fully ossified, 

 that the neurocentral sutures have disappeared in all the 

 vertebrae and that the osseous tissue is equally dense 

 in all the specimens. Traces of young have been most 

 carefully sought for, but most unfortunately not a bone of 

 a young animal has been found. 



The differences between the two forms of Iguanodon 

 are also not merely sexual. They are well marked and 

 certainly of specific value. The number of sacral vertebrae 

 seems to be quite constant in the several species of 

 Iguanodon, and Prof. Marsh, who has had several 

 hundred individuals of Dinosaurians through his hands, 

 representing numerous genera and species, has made 

 use, amongst other characters, of the number of sacral 

 vertebras present as generic distinctions. After carefully 

 comparing full size drawings of the bones with those of 

 the type specimen of /. Mantelli (Owen) in the British 

 Museum, M. Dollo is quite convinced that his smaller 

 form with five sacral vertebra; is identical with this. 

 There are two other well identified species of Iguan- 

 odon known, namely, /. Prestwichii and /. Seeleyi of 

 Hulke. The larger form from Bernissart cannot be /. 

 Prestwichii, which has only four sacral vertebra;, but it is 

 ju t possible that it may be identical with /. Seeleyi, 

 since its large bones resemble closely those described by 

 Mr. Hulke as characteristic of that species. There is, 

 however, this remarkable discrepancy. Mr. Hulke dis- 

 covered bony plates, forming as he believes a dermal 

 armour over the tibia of /. Seeleyi. Now amongst the 

 remains obtained from Bernissart are specimens of the 

 integument of both /. Mantelli and the larger form. 

 And these indicate that the skins of both these animals 

 were either quite naked or at the most covered with epi- 

 dermic scabs. M. Boulenger's name, /. Bernissartensis. 

 is re:ained for the larger Bernissart form, for even if 1. 

 Seeleyi should prove in the end to be identical with it that 

 name must fall through lack of priority. M. Dollo, taking 

 into consideration the resuhs as yet attained by him, 

 characterises the order Ornithopoda of the Dinosauria 

 to which the family Iguanodontida; belongs as follows : — 



Ornithopoda. — Foot digitigrade, ungulate, five functional 

 digits on the hand and from three to four on the foot. 

 Pubis projecting freely in front ; post-pubis present. Ver- 

 tebra; solid. Anterior limbs reduced, limb bones hollow. 

 Premaxillaries toothless, at least in their distal region. 



And the family Iguanodontida thus : — 



A single row of teeth. Three functional digits on the 

 foot. Two s>mmetrical sternal plates. 



The pur of sternal plates were mistaken by Professor 

 Marsh, who studied them in specimens in the British 

 Museum, for clavicles ; and the presence of clavicles was 

 included by bim in his definition of the family Iguanodon- 

 tida; ; but in the Bernissart specimens the pair of bones 

 are found in many specimens preserved in their natural 

 relations, and are seen at once to be sternal, clavicles 

 being altogether absent. A specimen is figured by M. 

 Dollo, in which the two sternal bones with the coracoid 

 and scapula of one side are seen in situ, all in their proper 



