432 
ACTIXOPTEKYGII. 
reticulating ridges. Scales marked with few prominent straight 
ridges, almost directly transverse, and terminating in acute denti- 
culations on the hinder margin; also with few fine vertical 
striations close to and parallel with the anterior margin of the 
exposed area. 
Form. Loc. Calciferous Sandstones (Cement-stone Group): 
Eskdale, Dumfriesshire. 
P. 4069. Three well-preserved specimens. Purchased , 1883. 
P. 5980. Specimen wanting paired fins. Purchased , 1889. 
The three species defined below are now assigned by Traquair 
(Ann. Hag. Nat. Hist. [6] vol. vi. 1890, p. 493) to a distinct genus, 
Mesopoma , “ on account of the more typically Palseoniscid con¬ 
figuration of their facial bones/’ As, however, “ the dentition is 
not yet ascertained in any of these forms, it seems also somewhat 
premature to proceed to the splitting of genera upon these dis¬ 
tinctions ” (Trans. Hoy. Soc. Edinb. vol. xxx. p. 47). 
Canobius pulchellus, Traquair. 
1881. Canobius pulchellus , R. II. Traquair, Trans. Hoy. Soc. Edinb. 
vol. xxx. p. 51, pi. v. figs. 9-13. 
1890. Mesopoma pulchellum, R. H. Traquair, Ann. Mag. Nat. Hist. [6] 
vol. vi. p. 493. 
Type. Fishes; Geological Survey of Scotland. 
Length of head and opercular apparatus almost equal to the 
maximum depth of the trunk, which is contained slightly more 
than four and a half times in the total length. Cranial roof-bones 
tuberculated; facial bones ornamented with delicate ridges, usually 
flexuous, sometimes passing into tubercles. Scales ornamented 
with a few vertical ridges close to and parallel with the anterior 
margin, each reflexed below, and becoming directed backwards 
parallel to the inferior margin, while the remaining postero-superior 
area is occupied with ridges' nearly parallel with the upper margin 
and terminating at the posterior border in denticulations. 
Form, Loc. Calciferous Sandstones (Cement-stone Group): 
Eskdale, Dumfriesshire. 
P. 4067. Specimen showing portions of all the fins except the 
pectorals. Purchased , 1883. 
