FISH LIZARDS 



2615 



spinal marrow, so that these two portions are always found detached. The bones 

 of the shoulder girdle much resemble those of lizards, the collar bones being well 

 developed, and the T-shaped iuterclavicle 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 OF FISH LIZARD, SHOWING YOUNG ONE WITHIN THE CAVITY OF THE RIBS. 



(One fourteenth natural 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 borfes 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 botre, 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 admi- 

 rably 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 

 PART OF THE FORE PADDLE OF A FISH LIZARD. of small finlets, while the extremity of 



hu. bone of upper arm; r. u. bones of fore-arm; the t } le ta jj was expanded into a horizontal 

 other letters indicate the bones of the wrist, below 

 which are the bones of the fingers. fin, Comparable to the flukes of a whale. 



