CESTRACIONTID^. 
289 
P. 2165 C. Small spine, probably posterior, with large denticles upon 
a median ridge, exserted 0*145. Egerton Coll 
P. 2165. Similar spine, exserted 0*2. Egerton Coll 
P. 2818. Imperfect posterior spine. Enniskillen Coll 
P. 4175. Fragment of spine; Lias, Normandy. Enniskillen Coll 
Acrodus anningise, Agassiz. 
1837. Hybodm curtus, L. Agassiz, Poiss. Foss. vol. iii. p. 49, pi. viii. b. 
figs. 4-6 (dorsal fin-spines). 
1839. Acrodus undulatus —■ Acrodus anningice , L. Agassiz, tom. cit, 
p. 144, pi. xxii. fig. 4. 
1864. Acrodus anningice, E. C. H. Day, Geol. Mao*, vol. i. n. 57 
pis. 111 .. 1 Y. 
J~yp e . Series of teeth, artificially arranged; British Museum. 
A species closely related to A. nobilis, but smaller, the principal 
teeth not measuring more than 0*03 in length. Coronal contour 
oi the teeth less rounded than in A. nobilis , and the superficial 
wrinkles coarser. Anterior teeth moderately elongated, almost in¬ 
variably with well-marked lateral prominences ; a median symphy- 
sial series present. 
It is still uncertain whether this “ species ” may not be founded 
—at least in part—upon the immature individuals of A. nobilis ; 
but the Collection does not afford any very definite evidence of a 
passage between the two forms, and one specimen at least (No. 37371) 
seems to show that in A. nobilis the dorsal fin-spines were relatively 
smaller than in A. anningice. In this species, however, as in A. 
nobilis , the principal teeth of one jaw appear to be smaller than 
those of the other; and the former is proved to be the upper by 
specimen No. P. 2146. 
Form. $ Loc. Lower Lias : Dorsetshire, . 
All the following specimens were obtained from the neighbourhood 
of Lyme Begis. 
P. 2731. Type specimen, consisting of forty teeth, probably found 
associated, but artificially and incorrectly arranged. 
Enniskillen Coll. 
P. 3153. The crushed anterior portion of a small fish, exhibiting a 
few of the teeth, shagreen, and the first dorsal fin-spine. • 
The shagreen consists of minute slender conical tubercles, 
longitudinally grooved, and sometimes fused into groups 
of two and three, as in Hybodus. The dorsal spine is 
much compressed laterally, and marked by sharp even 
ribs, widely spaced. Enniskillen Coll. 
TJ 
