\Revieics — DoUo's Dinosaitria of Bernissart. 81 



long narrow slits, which diverge anteriorly. The scapula is 

 relatively slender and elongated, being eight times as long as wide. 

 The coracoid is pierced by a foramen placed near to the scapular suture. 

 The posterior border of the coracoid is rounded — the sternal elements 

 are relatively small. The fore limb is half the length of the hind 

 limb. The humerus is relatively short. The manus is nearly one- 

 fonrth of the length of the limb. The imgual phalange of the first 

 digit, which forms a sort of spur, is one-thii'd the length of the 

 longest digit. The metacarpal bones are compressed together 

 laterally, indicating a relatively narrow extremity. There are five 

 sacral vertebrae. The pre-acetabular process of the ilium is nearly 

 one-half the length of that bone. The pre-j)ubis is short, thin, and 

 expanded ; its length, depth and thickness being expressed, in 

 millimetres, by the numbers 400, 200, 10. The large lateral 

 trochanter of the femur is in the middle of the length of the bone. 

 The tibia is relatively long. 



On every one of these points of structure the animal named 

 Iguanodon Bernissartensis differs, so that the animal may be defined 

 in comparison with I. Mantelli as being more massive in all its 

 proportions ; and it is about thirty-three feet long. The skull is 

 relatively broad, the width being half its length, which measures 

 65cm. The anterior nares do not descend so low upon the lower 

 jaw, while the length of the anterior narine is contained three times 

 in the length of the lower jaw. The orbital vacuity is elongated 

 vertically. The temporal fossa are each wide and four-sided in 

 form. The scapula is relatively stouter and shorter, being six times 

 as long as wide. The coracoid is pierced by a foramen, which takes 

 the form of a notch, opening posteriorly towards the humerus. 

 The sides of the bones are excavated, and their posterior borders 

 diverge, as if to receive sternal elements. The large sternal bones 

 are relativelj'^ strong. The fore-limb is two-thirds as long as the 

 hind limb, so that the proportions of the extremities are more 

 nearly equalized. The humerus is relatively longer, and the manus 

 shorter, being scarcely one-fifth the length of the limb. The first 

 .digit has its spur-like, inwardly directed, terminal phalange, half 

 as long as the longest digit. The metacarpal bones are sub-quadrate 

 in transverse section. There are six vertebra in the sacrum. In 

 the pelvis, the pre-acetabular part of the ilium is only one-third of 

 its total length. The pre-pubis is long, massive, and straight. Its 

 length, depth and thickness being expressed in millimetres by the 

 numbers 700, 170, 40. The large lateral trochanter on the femur 

 is situate in the lower third of the bone. The tibia is relatively 

 shorter. 



The author then goes on to discuss the taxonomic value of these 

 differences, considering three hypotheses. First, whether the two 

 varieties are to be attributed to age ; secondly, whether the differences 

 may be individual or sexual ; and, thirdly, whether they afford, 

 evidence of two species, or indicate two genera. M. Dollo con- 

 cludes that the differences enumerated constitute a species. This 

 conclusion is based on a consideration of the characters by means of 



DECADE in, — VOL. IT. — NO. 11. 6 



