WOODWARD : FOSSIL FISHES OF THE UPPER LIAS OF WHITBY. 335 
the inner face of the scale ; and above this at the upper margin 
there is a minute articular peg. The third scale, shown from the 
outer aspect in fig. 4, evidently belongs to the caudal region, and 
the angles of its overlapped border are much less produced than 
those of examples from the abdominal region. 
Taking into consideration all the specimens of the Whitby 
fish thus described, it is possible to form a tolerably complete idea 
of its principal external characters. We are, therefore, able, more 
satisfactorily than ' hitherto, to diagnose the species and determine 
its relationships to the other known forms of Lepidotus. 
The first interesting point is the discovery of the vomerine 
dentition, which comprises stouter teeth more adapted for grinding 
than those on the margin of the jaws. The second most striking 
feature is the new demonstration that the overlapped border of the 
abdominal flank-scales is as much produced at its anterior angles as 
in the later fishes which are referred to Lepidotus. The recognition 
of the supramaxillary bone adds a new feature of resemblance 
between Lepidotus and Dapedius ; while the renewed demonstration 
of the absence of a gular plate proves the generic distinctness of 
even the most generalised species of these two types. For Lepidotus 
semiserratus is indeed one of the most generalised species of its 
genus ; exhibiting no ossified vertebral rings, no irregular sub- 
division of the cheek-plates and supratemporals, and no excessiv^e 
development of grinding teeth, such as characterise many of the 
later forms. 
Comparing the Whitby species with the other known forms, it 
is clearly most closely related to the type species of the genus, 
Lepidotus elvensis, from the Upper Lias of Wiirtemberg, Bavaria, 
Northern France, Northamptonshire, and Somersetshire.* It is also 
very similar to the somewhat smaller earliest known species of true 
Lepidotus, the so-called Prolepidotus gallineki, from the Rhsetic 
formation of Neudorf, near Landsberg, Upper Silesia, t From these 
* iSee references in Catal. Foss. Fishes, B. M., pt. iii., p. 84. 
t R. Michael, Ueber eine neue Lepidosteiden-gattung aus dem oberen 
Keuper Oberschlesiens, Zeitschr. deutsch. geol. Gesell., 1893, pp. 710-729, 
pis. xxxiii., xxxiv. 
