MORPHOLOGY OF THE COAL MEASURES AMPHIBIA. 31 



(s) Scales (fig. 10 and plate 24, figs. 2 and 3) are present on the body of (462, 485) 

 several species. It is a matter of regret that their preservation is so imperfect 

 that nothing can be found out as to their structure. The Linton species, which pos- 

 sess scales, are, of course, carbonized and hence impracticable for microscopic study, 

 and in the Mazon Creek species of Amphibantiis and Micrcrpetou the scales have 

 been replaced by kaolin. The bodies of two species (Cercariomorphus parvisquamis 



- 



a 



FIG. 10. Horny armor of back of Hylonomus. a, imbricated scales; b, horny plates; 

 c, horny spines or tubercles; d, small imbricated scales. (After Dawson, based on 

 a photograph.) 



and Ichthyerpeton sqnamosum) of the Linton Coal Measures Amphibia were com- 

 pletely scaled. The scales in the Branchiosauria (462), so far as they have been 

 observed, are slightly imbricated; rounded, with concentric markings after the 

 manner of the modern cyprinoid fish-scale. They are extremely minute, and whether 

 or not they covered the entire body of the animal is unknown. On the body of 

 Cercariomorphus the scales have the appearance of being tubercular without 

 imbrication, and they apparently covered the entire bodily surface of the animal. 



