STRUCTURE AND AFFINITIES OF THE PLATYSOMID. 361 
from the internal aspect, is also displayed in the specimen, being displaced and 
dislocated below the other. The palate is not seen, but we might indeed be 
tempted to assume that it was as in Hurynotus amply supplied with crushing 
teeth. 
It is, therefore, clear that Hurysomus is a genus which, far from being 
identical with Platysomus, difters from it, as we shall afterwards see more fully, 
not only in its dentition, but also in its fins and the form of some of the bones 
of the head. And precisely in these respects it approaches the carboniferous 
genus Mesolepis, from which it indeed differs principally in the more broadly 
triangular shape of the mandible and in the shape of the teeth, which, although 
pedunculated have their crowns much flattened instead of being bluntly conical. 
Genus V. Wardichthys, Traquair, 1874. 
Wardichthys cyclosoma was described by myself in 1874* from a single 
Specimen contained in an ironstone nodule which occurred in the Lower 
Carboniferous shales (Calciferous Sandstone series) of Newhaven (Wardie), near 
Edinburgh. It is not a little remarkable, as well as unfortunate, that notwith- 
standing the large number of ichthyolites which have been collected in this 
locality, no other specimen of the fish, not even a detached scale, has ever been 
obtained. The name Wardichthys was bestowed upon it, not in reference to 
the locality, but in honour of my friend Mr Warp of Longton, whose untiring 
industry in collecting the fishes of his district has contributed so very largely 
to the advancement of our knowledge of Carboniferous ichthyology. 
Structure.—The length of the specimen is three inches, but, as the Am 
fin is entirely wanting, its original length was probably about four. The body 
is nearly circular, the dorsal convexity being, however, considerably greater 
than the ventral. The head is large, and several of the bones can be distinctly 
made out (Plate IV. fig. 12). Posteriorly there are two parietals (p) meet- 
ing each other in the middle line, and on the outer side of each is a small 
squamosal (sq). In front of the parietals are two more elongated /rontals (/), 
and again on the outer side of each frontal is a large posterior frontal (pf), the 
anterior part of whose outer margin apparently takes part in the posterior- 
superior boundary of the orbit. In front of this there is another plate (a. /) 
forming in like manner the anterior-superior boundary of the orbit, and which 
is clearly equivalent to the anterior frontal of Mesolepis, &c., but the median 
superethmoidal cannot be made out. Below this a portion of bone is seen in 
front of the maxilla, which is probably the preemaxilla. The orbit is thus seen 
to be placed as in Mesolepis, nearly right above the maxilla, but no circum- 
orbitals are recognisable. A portion of a slender hyomandibular is seen; it 
* Ann, and Mag. Nat. Hist. (4), vol. xv. 1874, p. 262, plate xvi. figs. 1-5. 
