1897.1 NEW PALEOZOIC VERTEBRATA. 83 



BATRACHIA. 



Ctenerpeton alveolatum, gen. et sp. nov. PI. Ill, Fig. i. 



C/iar. gen. — Limbs present ; neural spines and chevrons of 

 caudal vertebrae fan-shaped. Ribs present, not alate. Abdomen 

 protected by dermal scuta in series, which form chevrons directed 

 forwards, which terminate on each side of the belly in a series of 

 prominent, elongate and flattened scuta, which form a ledge or 

 shelf on each side. 



This genus is founded on a specimen on a block of coal shale 

 which is so broken that the head is wanting, and no thoracic plates 

 are preserved, although a considerable part of the right fore limb is 

 present. A trace of bones of a hind limb appears, and it is prob- 

 •able that these members were present, but of small size. The 

 affinities of Ctenerpeton are with Oestocephalus, Ptyonius and Uro- 

 cordylus, as indicated by the characteristic caudal vertebrae. It 

 differs from the first two in the robust scales which protect the 

 belly, and from all three in the presence of an external series of 

 longer flat scales, which form a prominent border, perhaps more or 

 less free, on each side. These resemble the closely placed teeth of 

 a coarse comb, and give the name to the genus. I have not 

 observed this character in any other genus of Stegocephalia. 



Char, specif. — Each abdominal dermosseous rod consisting of 

 three segments; the median, which forms the angle of the chevron, 

 the intermediate, which is long and slender, and the marginal, 

 which differs in form from the others. It is wider at the base, and 

 is curved gently backwards, terminating in a gradually contracted 

 obtuse apex. It is marked with delicate grooves which run out on 

 the posterior margin, and on the extremity. The anterior edge is 

 slightly overlapped by the posterior edge of the plate immediately 

 preceding. The anterior plates of the external series are short and 

 obtuse. The posterior edge of the rods of the median and inter- 

 mediate series is impressed by a single series of small pits like the 

 shallow alveoli of closely placed small teeth. The neural fans 

 of the caudal vertebrae are considerably wider than the haemal 

 fans, and are divided nearly to the base by a shallow groove, 

 which is not present on the h^mal fan. The fans are of about the 

 same length, and about twice as long as the body of a vertebra. 

 The marginal portion is marked with ten or a dozen short longitu- 

 .dinal grooves, which cut the truncate edge. 



