IGUANODON, THE. 



ILLINOIS. 



437 



and twenty-one of the species I. Bernissartii. 

 M. Depauw has set up and mounted one of the 

 skeletons, which he has been able to restore 

 nearly complete, except for a few phalanges 

 and other minor details. Some interesting con- 

 clusions have been deduced from the labors of 

 these two naturalists. The iguanodon belonged 

 to the sub-class of dinosaurians and the order 

 Ornithopoda, or bird-footed. Among the spe- 

 cial characteristics of the family are a single 

 row of teeth, three functional digits on the 

 foot, and two symmetrical plates, which Prof. 

 Marsh regarded, from studies in the British 

 Museum, to be clavicles, and in which he traced 

 a point of structural resemblance with birds, 

 but which M. Dollo declares, from the Bernis- 

 sart specimens, to be sternal plates. Accord- 

 ing to M. Dollo's restoration, the animal stood 

 on its hind-limbs and maintained an erect po- 

 sition, like the birds. Several different lines 

 of coincidence tend to prove this supposition 

 to be correct. Among them are the remarka- 

 ble ressmblances between the structure of the 

 pelvis and posterior limbs of birds and that 

 of the corresponding parts in the iguanodons. 

 Points of resemblance of the ilium and ischium, 

 indicated by Prof. Huxley twelve years ago, 

 are fully confirmed. The pubis is very large 

 in the iguanodon, and projects forward and 

 outward, forming an obtuse angle with the 

 post-pubis. The post-pubis is long and slen- 

 der, and directed backward alongside the is- 

 chium, as in birds, for a considerable distance 

 .beyond the ischial tuberosity. M. Dollo is in- 

 clined to agree with Prof. Marsh in identifying 

 the dinosaurian pubis with the pectineal pro- 

 cess of birds a conclusion which is supported 

 by the recently published observations of Miss 

 Alise Johnson, of Cambridge, England, U 0n 

 the Development of the Pelvic Girdle in the 

 Chick," in which it is shown that in the em- 

 bryo fowl the cartilaginous representative of 

 the pectineal process is at first much larger and 

 more prominent in proportion to the develop- 

 ment of the pelvis than subsequently, and be- 

 comes gradually reduced as development pro- 

 ceeds. The fore-limbs are considerably shorter 

 than the hinder one?, and are massive and 

 strong; the volume of the head and thorax is 

 considerably reduced a? compared with that 

 of reptiles generally ; and the position of a 

 large mass of the viscera is behind the hip- 

 joint, as is the case with birds. These facts 

 tend to support the theory that the posture 

 . of the animal was erect, for they indicate that 

 a considerable proportion of its weight was 

 thrown back, whereby, with the aid of the 

 long tail, its body was more easily and securely 

 balanced in that position. Further evidence 

 in the same direction is given by the number 

 of toes, which were five on the fore-feet, and 

 four, leaving a three-toed track, on the hind- 

 feet. The tracks of the iguanodon in the 

 Weaklen which could not have been made 



KT any other of the known dinosaurians of the 

 rrnation are three-toed. M. Dollo has com- 



pared the hind-feet of the fossils with these 

 tridactyl foot-prints, and has found them to fit 

 accurately. If the iguanodon had walked on all- 

 fours, it would also have left five-toed tracks, 

 while none such have been found. Another 

 structural resemblance to birds has been traced 

 in the fact that the dorsal spines of the verte- 

 brae are connected by a set of ossified ligaments 

 binding the whole dorso-lumbar region into a 

 rigid mass. The head is relatively small, and 

 is very much compressed from side to side. 

 The nostrils are spacious, and chambered in 

 their anterior region ; the orbits are of moder- 

 ate size, and elongated along the vertical. The 

 temporal fossa is limited above and below by 

 a bony arch, a disposition which is otherwise 

 found among living lizards only in the Hatteria. 

 The distal extremities of both jaws are without 

 teeth ; while there are ninety-two teeth in the 

 hinder parts of the jaws, and these, as with 

 other reptiles, were replaced by new ones as 

 fast as they were worn out. The skin was 

 smooth, or covered only with epidermic scales. 

 Some observers believe that they have found 

 in the foot-prints of the iguanodon evidences 

 that a slight web existed between the toes. 

 The first finger, or thumb, constitutes a horny 

 spur, the remains of which are supposed to 

 have led Dr. Mantell to believe that the igua- 

 nodon had a nasal integumental horn. In re- 

 storing and setting up the skeleton represented 

 in the figure, M. Depauw was a little embar- 

 rassed by the fact that some of the bones 

 could not be separated from the matrix ; con- 

 sequently, the restoration has a degree of stiff- 

 ness, but not enough to attract the attention 

 of casual observers. As the skeleton stands, 

 the tip of the snout is fourteen feet two inches 

 from the ground, and the horizontal length, 

 from the tip of the tail to a point immediately 

 under the tip of the snout, is twenty-three feet 

 nine inches. M. Dollo has drawn a conjectural 

 outline of the body of the animal, which is rep- 

 resented in the engraving. Leaving out the 

 long tail, its general shape is like that of a 

 duck. The sectional view, represented by X, 

 indicates that the animal was relatively nar- 

 row and sharp-keeled. The tail was shaped 

 like that of the crocodile, and was probably a 

 powerful swimming organ. The neck was 

 comparatively slender and capable of free 

 movements. The iguanodon was an inhabit- 

 ant of marshes so far as is known, of fresh- 

 water marshes only and probably fed on 

 large ferns, many of which were found with 

 the Bernissart specimens. 



ILLINOIS. State Government. The following 

 were the State officers during the year: Gov- 

 ernor, Shelby M. Cullom, who resigned Feb- 

 ruary 7th, and was succeeded by Lieutenant- 

 Governor John M. Hamilton (Republican); 

 Secretary of State, Henry D. Dement ; Treas- 

 urer, John 0. Smith ; Auditor, Charles P. Swi- 

 gert; Attorney-General, James McCurtney; 

 Superintendent of Public Instruction, Henry 

 Raab. Judiciary, Supreme Court : Chief -Jus- 



