164 AIR-BREATHERS OF THE COAL PERIOD. 



(2) Another portion of cuticle, similarly marked, appears to 

 preserve the form of the posterior part of the body and tail of the 

 animal, and also a mark representing the point of attachment of 

 the hind leg ; near to which, and along the dorsal ridge, is a por- 

 tion of the skin covered with much smaller scales. It is repre- 

 sented in PL I, fig. 5. This was found in close proximity to a 

 mass of bones of Dendrerpeton Oiveni, mingled with some of Hy- 

 lonomus Lyelli. 



(3) A third and still larger surface of integument with similar 

 markings, has upon it a number of vertebras and detached bones 

 of the small reptile Hylonomus Wymani, to be described in the 

 sequel; for which species however it would be much too large a- 

 covering. 



(4) Another well preserved fragment, less than two inches in 

 length, exhibits very different markings. It is nearly covered 

 with very small imbricated scales, thicker than those on the spe- 

 cimens previously described. On either side of what seems to 

 have been the middle line of the back, there is a series of pointed 

 fiat horny processes, which probably formed a double spinous crest. 

 Without these there are tufts of strong bristles, and exteriorly to 

 these last are rows of flat, thick, horny plates, transversely wrink- 

 led. Near to these was a row of conical truncated tubercles. 

 Sections of these appendages show them to have been horny and 

 attached to the cuticle. None of them have bony structure.. 

 Figs. 23, 26, 27, 28, 29, 30, PI. IV, represent this portion of cu- 

 ticle, with magnified views of its markings, and of the structure of 

 one of the thicker scales. Fig. 26 shows a portion of the ordi- 

 nary scaly skin magnified and viewed by transmitted light. Fig. 

 27 exhibits a few of the bristle-like appendages from the point 

 marked a in fig. 23. Fig. 28 shows four of the bluntly-conical 

 points seen in a portion of skin a little beyond the margin of the 

 fragment in fig. 23, but evidently belonging to it. Fig. 24 is an 

 enlarged representation of one of the flat horny scales from the 

 po'nt b in fig. 23 ; and fig. 29 is a magnified section of a por- 

 tion of the same scale, showing a compact translucent brown 

 substance with round canals, and near the margin, a portion much 

 more abundantly supplied with these apparently vascular canals, 

 while without this part there is a thin layer of more dense mate- 

 rial. Fig. 30 shows a portion of the surface of fig. 23, more 

 highly magnified, and displaying at a ordinary scales, at b 

 horny pointed organs, at c bristly appendages, and at d large 



