170 EXTINCT MONSTERS 
direction. Plate XXIV., which is a restoration, should be compared 
with the drawing of the skeleton in Pig. 58. Another important 
feature of the skeleton is the remarkable ossified tendons, by 
means of which the neural spines of the vertebrae were held 
together, and so strengthened. They increase in number in the 
region of the thighs, and also in the first part of the tail. 
The reader will have noticed the smallness of the fore limbs 
compared with the hind limbs. This is often the case with 
Dinosaurs. Only three fingers of the hand were used — the first 
was a rudimentary one ; the second and third were of nearly 
equal length, the fourth shorter, and the fifth entirely wanting. 
These long fingers ended in hoofs, not claws ; the fore limb as a 
whole was adapted for walking and support, rather than for 
purposes of prehension, although the latter might have been 
expected from its small size and position. The hind limb has 
three digits, all well developed and massive. These were covered 
with fairly broad hoofs, and it is clear that this Dinosaur was in 
the habit of walking on its hind legs. It is distinguished from 
Hadrosaurus, a near ally, by the fact that its limb-bones, instead 
of being hollow, are all solid. This piece of evidence tends to 
confirm the idea that Claosaurus was fond of the water ; for it has 
been pointed out by Owen, Marsh, and other authorities, that 
land animals, having to support the weight of their bodies on 
land, have hollow bones ; while those which live in the water, like 
whales, being buoyed up by the action of the water, and thus 
having so much weight taken off their hands and feet, have their 
limb-bones solid. 
The late Professor von Zittel considered that possibly Claosaurus 
was not to be distinguished from Hadrosaurus. 
There is an unusually fine example of a mounted skeleton in 
the United States National Museum (Washington), to which the 
