﻿432 ACTIXOPTERYGII. 



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. 4' Loc. Calciferous Sandstones (Cemeni>stone Group) : 

 Eskdale, Dumfriesshire. 



P. 4069. Three well-preserved specimens. Purchased, 18S3. 



P. 5980. Specimen wanting paired fins. Purchased, 1889. 



The three species defined below are now assigned by Traquair 

 (Ann. Mag. Nat. Hist. [6] vol. vi. 1890, p. 493) to a distinct genus, 

 Mesopoma, " on account of the more typically Paheoniscid 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. Roy. Soc. Edinb. vol. xxx. p. 47). 



Canobius pulchellus, Traquair. 



1881. Canobius pulchellus, R. H. Traquair, Trans. Roy. 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. Sf Loc. Calciferous Sandstones (Cement-stone Group) : 

 Eskdale, Dumfriesshire. 



P. 4067. Specimen showing portions of all the fins except the 

 pectorals. Purchased, 1883. 



