Fossil Fishes from Dumfriesshire. 
493 
Mesopoma, gen. nov. 
Body fusiform, suspensorium only very slightly oblique, 
but the maxilla shaped as in typical Palasoniscidae. Dorsal 
fin nearly opposite the anal. 
I propose to separate from the genus Oanobius the species 
pulchellus ( op . cit. p. 51) and politus {op. cit. p. 53), on 
account of the more typically JPalseoniscid configuration of 
their facial bones. I should have included them in Rhadin - 
ichthys were it not for the very slight obliquity of the suspen- 
sorium, which excludes them from the definition of the genus 
along with another species from the Pumpherston oil-shales, 
which I recently described as Rh. macrocephalus * . These 
species will therefore in future stand as Mesopoma pulchellum, 
politum , and macrocephalum. 
Mesolepis tuberculatus , sp. n., Traq. 
Of this I have seen no really complete specimens. Such 
as have occurred show a small deep fish, about 4 inches in 
length and 2 in depth, with a large head occupying about one 
third of the entire length. From the structure of the head, 
so far as it is seen, the position of the dorsal fin which com- 
mences at the culminating part of the back, and the shape of 
the scales, which are high and narrow, there can be no doubt 
as to the species being referable to Mesolepis. The scales 
differ from those of any known species in being ornamented 
externally with a sharply defined tuberculation, the tubercles 
often tending to become confluent transversely. 
Locality. Glencartholm, Fskdale. Type in Edinburgh 
Museum. 
Mesolepis has not hitherto been recorded from strata below 
the horizon of the Millstone Grit. 
Mesolepis rhombus , sp. n., Traq. 
Length 5 inches; depth of body just in front of dorsal fin 
inches ; length of head contained a little more than three 
times in the total. Dorsal tin commencing at culminating 
point of back, high in front, then falling away to a fringe 
which ends close to the tail-pedicle ; anal fin short-based, 
triangular, acuminate ; caudal deeply cleft, heterocercal. 
Ventral fins small ; pectorals not seen. Scales rather small, 
narrow, their surface ornament badly preserved, but appa- 
rently consisting of rounded tortuous ridges, sometimes 
passing into tubercles, whose direction is mainly parallel with 
the anterior and posterior borders of the scale. Dentition 
not visible ; head conformable to the type of Mesolepis . 
* Proc. Roy. Soc. Edinb. tor 1889-90, p. 398. 
