STRUCTURE AND AFFINITIES OF THE PLATYSOMID. 355 
appearance, as if covered by a number of oval imbricating scales,—a similar 
appearance is seen on some of the branchiostegal rays. Unfortunately no 
teeth are visible. 
The curious form being evidently no Palwoniscus, but on the contrary 
standing out boldly as a hitherto unrecognised genus, I have bestowed upon it 
a new generic title, in honour of the eminent naturalist who first made it known 
to the scientific world ; and the structure of the head, as seen by the direction of 
the suspensorium and the position of the orbit, being clearly Platysomid, and in 
accordance with the disposition of the dorsal fin, I have transferred it to the 
family under examination. It resembles Hurynotus in the body being less 
deep than in the rest of the family, in the general aspect of the squamation (the 
singular ventral scales being left out of view) and in the form of the anal fin, 
but the dorsal has the position of that fin in Wardichthys. Benedenius may 
therefore be placed near EHurynotus as one of the most palzoniscoid, in general 
aspect, of the family Platysomide. 
Genus III. Mesolepis, Young, 1866. 
History.—The genus Mesolepis was first made known by Professor Youne 
in 1866, in whose original description we find the contour of the body and fins, 
and, in one species at least, the shape of the teeth correctly recognised : the 
figure of the scales given by him cannot, however, be said to give an accurate 
idea of their configuration. 
Specimens of Mesolepis (M. Wardi?), from the “ Drumgray ” coal shale at 
Carluke, occur in Dr Ranxtn’s collection, one of which gives an exquisite view 
of the mandibular teeth, with their “minie bullet-shaped” crown, elevated 
on a constricted neck or stalk. Is it not possible that this specimen may 
represent the Pododus capitatus, catalogued by Acassiz in his “ Tableau 
general,” as a “Sauroid” from the coal strata of the above named locality ? 
Certainly the name is descriptive enough of the peculiar form of the tooth. 
But as Acassiz left no description or figure behind him whereby Pododus — 
(and only too many other genera and species) might be identified, Youne’s name, 
Mesolepis, must be definitely adopted. 
Species.—Professor Youne has distinguished two species—M. Wardi, in 
which the length of the trunk is nearly twice its greatest depth, and the tail 
pedicle thick and elongate; and M. scalaris (Plate IV. fig. 1), in which the 
body is more arched dorsally, and the tail pedicle very short and slender. 
Iam indebted to Mr Binney of Manchester, and Mr BreresrorD WRIGHT 
of Aldercar Hall, Nottinghamshire, for the loan of two specimens of Mesolepis 
from the Dalemoor Rake Ironstone (Lower Coal Measures) of Stanton-by-Dale 
in Derbyshire, which seem to me to indicate yet another species, which I pro- 
VOL. XXIX. PART I. 4¥Y 
