170 PICTURESQUE SKETCHES 



tell yet more of its structure, and thence deduce 

 more clearly the habits of the animal. In one speci- 

 men of the paddle (fig. 62), obtained from Barrow- 

 upon-Soar, in Leicestershire, not only the bones, but 

 the actual outlines of the extremity of the fin, are 

 clearly defined, and are found to exhibit the impres- 

 sion of a number of rays extending downwards and 

 forking off towards the end. It is clear, from the 

 extreme rarity of their preservation, that these rays 

 were not bony, and they were probably either cartila- 

 ginous, or formed of that albuminous horn-like tissue, 

 of which the marginal rays of the shark's fin consist. 

 The fore part of the fin was terminated by a small 

 unbroken and well-defined line, probably only a thick- 

 ening of the skin; and the dimensions of the soft part, 

 compared with the skeleton, show that the total length 

 of the extremity would be about half as much again 

 as that of its bony and solid portion. 



The tail of the Ichthyosaurus was of great length, 

 the number of vertebrae extending beyond the hinder 

 extremities being very much greater than half the 

 whole number possessed by the animal. At about 

 the 30th vertebra from the pelvis there have been 

 observed, in most of the more perfect specimens, dis- 

 tinct marks of a fracture, this portion of the tail being 

 generally bent off at an angle. -At the same point, 

 too, there is generally a slight displacement of a few 

 of the bones. This, however, is not all. At the 

 point thus indicated a modification of the form of 

 the vertebra has been observed, so that the rest 

 (forming the tail) have a somewhat oblong shape, 

 just the reverse of what is known to occur in the 

 whale, where these bones are a little flattened. Now 



