312 
SELACHII. 
Var. flettonensis. Tuberclns upon tho dorsal fin -spines com- 
paratively small, fused into rldgos distally. Teeth of series iv. 
narrow ; coronal prominence in most teeth well marked. 
39475. Fragment of spine ; Upper 0.x.ford Clay, Chippenham. 
Purchased, 1865. 
P. 5881. Plaster cast of cephalic spine, dcscrihod and figured by the 
present writer, loc. cit. p. 3-10, pi. xii. figs. 7, 8 ; Oxford 
Clay, Flctton, near Peterborough. 
Made in the Museum, 1888. 
47440. Forty-four associated teeth ; Fletton. Two of series iv. are 
shown, of tho natural size, in Plato XV. fig. 14. 
Sharp CoTl. 
I. Species founded upon detached dorsal Jin-spines with which the 
teeth have not yet been found associated. 
Asteracanthus aexnisulcatus, Agassiz. 
1837. Asteracanthus semisulcatus, L. Agassiz, Poiss. Foss. vol. hu 
p. 34, pi. vili. a. figs. 7, !), 10 (P fig. 8). 
1871. Asteracanthus teuuistriatus, J. Phillips, Qeol. Oxford, p. 178, 
diagi-. xxxviii. fig. 7. 
Ty2>e. Imperfect dorsal fin-spine ; British Museum. 
Dorsal fin-spine about equal in size to that of A. acutus, hut less 
laterally compressed and more robust ; anterior face rounded, but 
keeled ; posterior face slightly convex, with largo denticles. Orna- 
mental tubercles relatively large, elongated, arranged in close series, 
often fused iu part into short ribs. 
The teeth of this species are probably described under the name 
of Strophodus magnus, Agassiz. 
Form. ^ Loc. Great Oolite : Oxfordshire. 
P. 2855. Typo specimen described and figured by Agassiz, loc. cit. 
fig. 7 ; Stonosfield Slate, Stonesfleld. Ennislcillen Coil- 
'S. 463. A smaller imperfect spine associated with this species by 
Agassiz {loc. cit. fig. 8), but exhibiting striking resem- 
blances to A. acutus ; Stonosfield. Eyerton Coll. 
P. 2856—7. Two abraded fragments of spines equal in size to the 
type, and one imperfect larger specimen ; Stonosfield. 
Ennisl'illen Coll. 
