164. FOSSIL FISHES OF THE ENGLISH CHALK. 
form a conspicuous serration. The scales of the next row are much deeper than 
wide, with the upper end rounded or truncated. Above these the scales are 
doubled in depth, and rapidly taper to a blunt point at the upper end. Next there 
is a row of still more deepened scales, which are remarkably slender and tapering 
in their upper two thirds, and appear to terminate the squamation of the flank. 
The vomer is unknown, but both the splenials are exhibited in Dixon’s fossil, 
and that of the right side is shown in Pl. XXXIV, fig. 5a. In Dixon’s original 
figure the bones are somewhat diagrammatically restored, and two oval vacuities 
are wrongly represented in the outer toothless margin. This margin forms a 
thin, smooth lamina with a very sharp edge, without any vacuity. In the front 
third of the bone all the teeth are small and rounded, each with an apical 
pit; but behind these the characteristic row of principal teeth is seen in regular 
order. In the left splemial, the two posterior principal teeth are less elongated 
than the others and irregular in shape. In a larger specimen from Houghton 
figured by Dixon (op. cit., pl. xxx, fig. 14), the principal teeth are in a remark- 
ably regular series and approach the fragment of splenial dentition named 
Pycnodus eretaceus by Agassiz. There is, in fact, every gradation between the 
typical A. angustus and the latter form. A very small left splenial dentition from 
the Grey Chalk of Folkestone (Pl. XXXIV, fig. 4) is also probably referable 
to the young of this species. It shows very well the beginning of the row 
of principal teeth, each with a very shallow apical hollow; it also exhibits a 
crimping of the margin of the pitted crown in the smaller teeth (fig. 41). 
Horizons and Localities.—Turonian zones: neighbourhood of Lewes, Newtimber, 
and Houghton, Sussex. Zone of Micraster coranguinum; Northfleet, Kent ; 
South Croydon, Surrey. Zone of Micraster cortestudinarium: Purley, Surrey ; 
Borstal, Kent. Zone of Schloenbachia varians : Folkestone. 
2. Anomeodus willetti, A. S. Woodward. Plate XXXIV, fig. 5. 
1893. Anomeodus willetti, A. S. Woodward, Geol. Mag. [3], vol. x, p. 489, pl. xvii, fig. 1. 
1895. Anomeodus willetti, A. S. Woodward, Catal. Foss. Fishes B. M., pt. iii, p. 263. 
T'ype.—Imperfect skull with dentition, from the zone of Holaster subglobosus ; 
Brighton Museum. 
Specific Characters.—A small species, with teeth very irregularly arranged. 
Teeth of the principal series on the splenial bone obliquely set, very irregular in 
size and shape, wide mesially, tapering at each extremity, and not much broader 
than long; inner teeth relatively large, in one series, usually broader than long, 
with axis oblique; outer teeth in about three very irregular series, mostly smaller 
than the teeth of the inner series. Vomerine dentition anteriorly in three series, 
posteriorly in five, but extremely irregular; the largest teeth much antero- 
