PERMOCARBONIFEROUS AMPHIBIANS AND REPTILES 65 



name, Limnoscelis paludis, meaning marsh-footed reptile of the 

 swamps. This reptile reached a length of seven feet, and evidently 

 had food habits somewhat like those of the next group, though more 

 distinctly carnivorous and rapacious. 



The third group, which is composed of numerous known species, 

 varying in length from less than one foot to more than three, is 

 represented by Lahidosaurus (Fig. 7) . I am less certain of the pre- 

 cise details of this creature, since, aside from the skull, the skeletons 

 of the Chicago collection have not been fully worked out. The 

 restoration is based largely upon the figures of the mounted skeleton 

 in the museum at Munich, aided by various nearly complete 



Fig. 7. — Lahidosaurus hamalus, a cotylosaur reptile about four feet in length. 

 From Texas. 



skeletons of smaller forms. This group of cotylosaurs, the most 

 highly specialized of our American forms, appears to have been of 

 more distinctly terrestrial type than the others. Its limb bones 

 are more slender, and the claws are sharp and curved, unlike those 

 of other groups, where they are flattened terminal nails. Espe- 

 cially striking is the narrowed, beaklike skull in front, and the long, 

 curved, sharp, and rakelike teeth, which suggest their food-habit, 

 that of prodding in the mud and sand for soft-bodied invertebrates, 

 or possibly for detaching limpet-Hke 'creatures from the rocks. 

 The teeth of the jaws are arranged in two or more rows, used chiefl}' 

 for crushing their food, not so much for cutting or tearing. 



Still another family, the most lowly organized of all cotylosaurs 



