FISH-LIZARDS. 
25 1 
of the shoulder-girdle much resemble those of lizards, the collar-bones being well- 
developed, and the T-shaped interclavicle resting on the lower surface of these and 
the metacoracoids. The limbs are quite unlike those of any other reptiles, the 
upper bone (humerus in the fore-limb) being very short and thick, while below 
this the whole of the bones, as shown in the accompanying figure, were polygonal, 
and so articulated with one another that the skeleton of the paddles assumed a 
SKELETON OP FISH-LIZARD, SHOWING YOUNG ONE WITHIN THE CAVITY OF THE RIBS nat. size). 
(From Gaudry.) 
kind of pavement-like or mosaic structure. In most kinds the front paddles were 
much larger than the hinder-pair; and whereas, in some cases, two longitudinal 
series of bones originate from the bone marked i in the accompanying figure, thus 
producing a very broad type of paddle, 
in other forms (as shown in the skeleton 
in the figure above), only a single series 
articulated with that bone, and the whole 
paddle was consequently much narrower. 
Specimens like the one figured here show 
that while the soft parts of the paddle 
extended but a short distance in advance 
of the front edge of the bones, on the 
hinder-side they terminated in a wide 
fringe, thus forming a structure admir¬ 
ably adapted for swimming. Other 
examples indicate that the back of these 
reptiles was furnished with an upright 
triangular fin somewhat like that of a 
porpoise, behind which were a number 
of small finlets, while the extremity of 
the tail was expanded into a horizontal 
fin, comparable to the flukes of a whale. 
Many of these reptiles attained a length 
of from 30 to 40 feet; and they flourished throughout the whole of the Secondary 
period, that is to say, from the epoch of the Trias, or Red Sandstone, to that of the 
PART OF THE FORE-PADDLE OF A FISH-LIZARD. 
hu, bone of upper arm; r.u, bones of fore-arm; tlie 
other letters indicate the bones of the wrist, below 
which are the bones of the fingers. 
