192 
ACTIXOPTEBYGII. 
mostly radiating and each bearing a series of small tubercles ; these 
ridges on the dentary bone radiating from the symphysis, on the 
articulo-angular bone radiating from the mandibular articulation. 
Palatine bone produced forwards as a short cylindrical extension in 
advance of the ethmoid articulation, and the long slender tooth, 
antero-posteriorly compressed, fixed at its extremity at right-angles 
to the long axis of the bone ; the outer face of the premaxilla only 
sparsely ridged ; dentary rapidly contracting almost to a point at 
the symj)hysis, where it exhibits about three large irregular 
processes; the mandibular ramus considerably deepened behind, its 
maximum depth nearly equalling one third of its total length ; 
about six large mandibular teeth, all both slender and little curved. 
Teeth much compressed, and some delicately striated, none con¬ 
spicuously serrated on the edges. Operculum nearly two thirds as 
broad as deep, marked by numerous sharp, radiating, tuberculated 
ridges. 
The heads from the Turonian of Bohemia described under the 
name of Encliodus lialocyon, Ag., by A. Fritsch (Rept. ii. Fische 
bohm. Kreideform. 1878, p. 35, pi. vii. figs. 1-3) seem to differ 
from this species in the more slender proportions of the mandible. 
Form. Log. Senonian and Turonian: S.E. England. (?) Turo¬ 
nian : Saxony and Bohemia. , 
4004, 4049, 4157, 4160, 4180-81, 4183-84, 4186, 4198. The series 
of type specimens figured by Mantell and Agassiz, except 
the detached teeth, which are also probably in the Mantell 
Collection but not identifiable; Chalk, Lewes. The 
original of Agassiz, loc. cit. fig. 1, shows the left pre- 
maxilla from the inner aspect, with remains of the 
pterygo-quadrate arcade and mandible ; fig. 6 represents 
a portion of the ectopterygoid; figs. 9, 10 represent the 
extremity of the palatine; and figs. 14, 15 two imperfect 
opercula, Mantell Coll. 
P. 5415. Small skull and mandible, displaying the cranial roof, 
premaxilla, maxilla, and dentary, described and figured 
in Proc. Geol. Assoc, vol. x. p. 315, pi. i. fig. 5; Lewes. 
Presented hy P. E. Coom.be, Esq., 1888. 
25749, 25755, 25765. Imperfect right dentary, with two detached 
large teeth doubtfully of this species, figured by Dixon, 
op. cit.', Chalk, Sussex. Diccon Coll. 
4001, 4071, 4182, 4201. Two very imperfect small skulls, and two 
fragmentary mandibles ; Lewes. Mantell Coll. 
