ON THE CLASSIFICATION OF THE LABYRINTHODONTS. 187 
Lepidotosaurus, Hancock & Howse. 
There does not appear to be adequate ground for reckoning this fossil among the 
Labyrinthodonts. 
L. Durru, Hancock & Howse. 
Locality. Magnesian Limestone (Permian) of Midderidge, Durham. 
References. Hancock & Howse, Q. J. Geol. Soc. vol. xxvi. p. 556, t. xxxviii. 
[1870].—Reprint in Nat. Hist. Trans. Northumberland and Durham, vol. iv. 
p- 219, t. vi. [1871].—Brit. Assoc. Report for 1873, p. 245 [1874]. 
Leptognathosaurus, Barkas. 
This genus is not adequately characterized by Mr. Barkas, and the figure (of a 
mandible with teeth) does not enable us either to identify or discriminate the 
fossil. 
L. ELoneatus, Barkas. 
Locality. Low-Main Coal-Shale, Northumberland. 
References. Barkas, Coal-measure Paleontology, p. 160 [1873].—Atlas of Car- 
boniferous Fossils, t. x. fig. 236 [1873]. 
Leptophractus, Cope. 
The description of the superior surface of the skull does not yield any characters 
of which we can avail ourselves. ‘The teeth are rather distantly grooved for 
some distance above the base. They are of different sizes; the smaller are com- 
pressed and with fore-and-aft cutting edges... .. The smaller ones are close together, 
and their crowns are curved backwards; the larger ones are at more remote inter- 
vals; both have enlarged bases; whether both forms are in the same series I 
cannot determine.” 
“The Leptophractus was about as large as a medium-sized alligator.” 
L. oBSOLETUS, Cope. 
Locality. Coal-measures of Linton, Ohio. 
Reference. Cope, Proc. Acad, Nat. Sci. Philadelphia, 1873, p. 340. 
Macrosaurus, Barkas. 
A vertebral column, containing 80 biconcave centra, with numerous ribs attached. 
“The diameters of the larger vertebrae are 23 in., and the diameters of the smaller 
li in.” ‘The fossil is doubtless Labyrinthodont, but inadequately characterized. 
M. potysponpyLvs, Barkas. 
Locality. Low-Main Coal-Shale, Northumberland. 
References. Barkas, Coal-measure Paleontology, p. 57 [1873].—Atlas of Car- 
boniferous Fossils, t. vii. [1873]. 
Megalerpeton, Young. 
“Cranium narrower than that of Anthracosaurus in the proportion of 4 to 5; 
posterior nares between first and second pairs of tusks ; pterygomaxillary apertures 
commence an inch behind them; mandible tapering rapidly to symphysis, coarsely 
pitted externally ; teeth regular, equal, their base oval transversely to jaw ; crown 
circular, blunt, slightly recurved. The vertebree differ somewhat in proportion from 
those of Anthracosaurus; their transverse processes are oblique downwards, those 
of Anthracosaurus horizontal.” 
M. PLicmENs, Young. 
“ Convolutions sinuous, occupying larger part of transverse section, encroaching 
very much on pulp-cavity.” 
