PLATYSOMATIDJE. 
533 
Mesolepis scalaris, Young. 
1866. Mesolepis scalaris, J. Young, Quart. Journ. Geol. Soc. vol. xxii. 
p. 313. 
1875. Mesolepis scalaris, J. Ward, [Proc.] N. Staffs. Nat. Field Club, 
p. 235. 
1879. Mesolepis scalaris, R. H. Traquair, Trans. Roy. Soc. Edinb. 
vol. xxix. p. 355, pi. iv. tigs. 1-5. 
1890. Mesolepis scalaris, J. Ward, Trans. N. Staffs. Inst. Mining Engin. 
vol. x. p. 182, pi. vii. figs. 10-14. 
Type. Fish; collection of John Ward, Esq., Longton. 
Dorsal contour of trunk strongly arched, the maximum depth, at 
the origin of the dorsal tin, nearly equal to the length of the trunk 
from the pectoral arch to the base of the caudal tin ; caudal pedicle 
short and narrow. Head and opercular apparatus occupying about 
one-third oi the length to the base of the caudal tin ; teeth of lower 
jaw tumid distaily. Pelvic tins arising midway between the pec¬ 
torals and the anal; dorsal tin very high in front, its maximum 
height contained two and a half times in the depth of the trunk at 
its origin; caudal fin very large and deeply cleft. Tuberculations 
of scale-ornament confluent into short, fine, vermiculating ridges. 
Form. Sf Loc. Coal-Measures : North Staffordshire. K" 
Not represented in the Collection. 
The following specimen is of undetermined species. In some 
respects it is suggestive of M. rhomba; but although very coarsely 
rugose, the scales are at least as broad and large as in the type 
species. 
P. 4084. Fragmentary remains of the head and trunk, about 0-105 
in length, exhibiting regular coarse striations on the 
opercular bones, and an irregular rugosity of angularly 
bent ridges on the scales ; Calciferous Sandstone, Eskdale. 
Far chased, 1883. 
The following species have also been briefly described, but do not 
appear to be represented in the Collection :— 
Mesolepis microptera, R. H. Traquair, Trans. Roy. Soc. Edinb. 
vol. xxix. (1879), p. 356, pi. iv. fig. 8.—Lower Coal- 
Measures (Dalemoor Rake Ironstone) ; Stanton-bv-Dale, 
Derbyshire. [Imperfect fish; E. W. Binney Collection.] 
Mesolepis rhomba, R. H. Traquair, Ann. Mag. Nat. Hist. [6] 
vol. vi. (1890) p. 493.—Calciferous Sandstones (Cement- 
stone Group); Eskdale, Dumfriesshire. [Imperfect fish ; 
Edinburgh Museum.] 
Mesolepis tubercidata , R. H. Traquair, ibid. p. 493.—Ibid. 
[Ditto.] 
