292 
SEIACHII . 
slightly divided into two unsymmetrical emincuces, one 
smaller than the other, with traces of lateral denticles. 
Ef/erton Coll. 
P. 2734. night ])torygo quadrate and mandibular cartilages, with 
about twenty teeth, much displaced. Enniul'iUen Coll. 
39925. Plaster cast of the dentition probably of the lower jaw, 
described and figured by E. C. II. Day, loe. cit., and shown 
iu the accompanying woodcut (fig. 10); original in the 
collection of S. H. Deckles, Esq., of St. Leonards. 
Purchased, 18G0. 
P. 2732. Portions of the dental series ii. to vi. of one half of a 
similar, but larger jaw, shown of the natural size iu 
PI. XIV. fig. 4. The length of the teeth of the successive 
soi'ies is as follows : — ii. O’OlO, ui. 0'024, iv. 0'028, 
V. 0-U24, VI. 0-UlG. Slight indications of lateral pro- 
niineiices arc observed in nearly all the teeth, and the 
coronal contour is much raised in scries n. to iv. In 
series v. the teeth are very obtuse iu front, but gradually 
taper behind : and those of no. vi. are comparatively 
narrow, tapering at each extremity. Ennislcillai Coll. 
32751. A group of teeth, also probably of the lower jaw, having 
less elevated crowns than iu the last B])ecimon. 
Purchased, 1857. 
P. 2137-8. Three small groups of typical teeth. Ejerton Coll. 
32752. Eive detached teeth, the crown of one divided into two well- 
marked eminences, and three of the others approaching a 
similar form. Purchased, 1857. 
P. 2139. A posterior series of four small teeth, and nine detached 
teeth. Egerton Coll. 
P. 2745. Elongated principal tooth, the crown marked by two 
faint transverse constrictions. Ennislcillen Coll. 
As already remarked (p. 207) the dorsal fin-spines of Acrodus 
anningite can scarcely be distinguished from those of llyhodus 
reticulalus. They were first described by E. C. II. Day (Joe. cit.), 
who pointed out that the second dorsal formed the t 3 pe of Agas.siz s 
Uyhodus nirlus. The first dorsal is long and slender, and seems to 
differ from that of //. retieidatus iu the more rounded character of 
the ribs and the relulivoly wider spaces between those placed 
anteriorly. The posterior face bearing the denticles is not much 
