Scientific Lectures, 149 



animals inhabiting the sea have the upper and lower portions of 

 these bones drawn together, so that the animal can move laterallj 

 with the greatest facility, but not so easily vertically; while the 

 creatures occupying the land have the arrangement the reverse of 

 this, the sides being more closely drawn together, so that they can 

 move more easily vertically and not so easily laterally. Then here 

 we have the bones or spines, more or less elongated, according as the 

 weight of the outer coating may require. In the case of a reptile that 

 is heavily coated with armor, we find these spines very strong, and 

 with a kind of flat form on the summit, which will bear the outer 

 scale or plate, which is to act as defensive armor, serving to protect 

 the vital organs within, yet not so important or so complete a pro- 

 tection as the bony parts themselves. We have now to add to the 

 head, the lower jaw, and the teeth of the upper and lower jaw, the 

 length of one giving us the length of the other ; for I have often 

 been obliged to be contented with a very small fragment of either or 

 of each, as I shall presently show you. We have now to add the 

 limbs upon which all this is to be supported, and which give facilitj 

 of movement. We find here in front a portion of flattened bone, 

 which will hold this limb, so that it can move freely, then, this 

 second bone, coming from the shoulder. Then we have two bones 

 below ; I mean the reptile has, and so have we [laughter] ; and then 

 other bones corresponding to our hand, and there are five digits or 

 fingers. Then we have here the pelvic arch, represented by the 

 extension of these pieces of bone, and then we have the bones of the 

 leg, the two bones coming to the heel and ankle, for the reptile has 

 an ankle, although it may not be as pretty as some other ankles 

 [laughter] ; and then we have here four toes, terminated with claws, 

 more or less elongated, corresponding with the terminations upon 

 other feet, whether claws, or hoofs, or nails. This creature has a 

 very long tail, with spines above protecting the spinal cord, and with 

 projections below the tail, shaped like the letter Y, for the special 

 protection of the large blood-vessel necessary to give force to this 

 organ, which is its instrument of defense. These bones, shaped 

 like the letter Y, are more or less elongated, as the creature may 

 have more or less occasion to press the tail upon the ground, I 

 trouble you with this detail simply to prepare you for the large 

 animal that I have here, which is organized and constructed in pre- 

 cisely that manner ; and I want to show you that we can trace the 

 habits of the animal from these bones which form a part of his talL 



