AIR-BREATHERS OF THE COAL PERIOD. 165 



plates. The whole of these parts, though displaced by the flat- 

 tening and wrinkling of the skin, are in good preservation, and 

 show their characters in great perfection under the microscope. 

 They are all black and shining as if carved in jet. 



(5) Near this last portion of cuticle, and possibly belonging to 

 it, are pointed and probably membranous appendages, marked on 

 each side with rows of scales not overlapping, and each with a 

 pore in its centre. The manner in which these appendages are 

 bent and wrinkled, shows that they must have been soft, except at 

 the tips, which seem to have been hard and horny, and they are 

 arranged in series, as if originally placed along the sides of the 

 neck or abdomen, or both. These appendages are represented 

 in PL IV, figs. 31 and 32. A magnified representation of the 

 point of one of them is given in fig. 33, and a small portion, still 

 more highly magnified, in fig. 34. The use of these appendages 

 it is not easy to conjecture. They remind us of the gular pouches 

 of iguana, and of the lateral expansions of some geckos and of the 

 Draco volans. Possibly they formed lateral parachutes, aiding 

 the animal in moving over soft mud, or perhaps in leaping or 

 swimming. 



(6) Some other fragments appear to have belonged to a diffe- 

 rent species from either of the foregoing, and are represented in 

 PI. V. The best preserved specimen (Fig. 22), which is about 

 one inch in length and half an inch in breadth, is covered with 

 very small imbricated scales. It is crossed by six or seven obscure 

 ridges, which both at the bottom and along a mesial line, pro- 

 jected into points covered with larger scales. A row of large 

 scales with round pores, connects these along the lower side (Figs. 

 23 and 24.) If, as seems probable, this fragment belonged to the 

 side of the trunk or tail, it would perhaps indicate a division of 

 the sub-cutaneous muscles into an upper and lower band, as in the 

 newts. A separate fragment, with transverse horny ridges (Figs. 

 26 and 27), and another with a longer lobe similar in structure to 

 those above mentioned (Figs. 28 and 29), may perhaps be re- 

 ferred to the same animal. A larger patch of skin presents simi- 

 lar imbricated scales, but without a mesial line, and with an edg- 

 ing of larger scales (Fig. 25). 



Six species of reptiles have left their bones in the repositories 

 containing these remnants of cuticle. Of these, Dendrerpeton Aca- 

 dianum was an animal of too great size to have been clothed 

 with integument of this character and of such dimensions. Hylo- 



