134 
SELACHII. 
1878. Ptychodus mammillaris , St. Zarecznego, Sprawozdanie Komisyi 
Fizyjograf. Galicyi, vol. xii. p. 201, pi. viii. fig. 9. 
1885. Ptychodus mammillaris , F. A. Quenstedt, Handb. Petrefakt. 3rd 
edit. p. 282, pi. xxi. figs. 61, 62. 
Type. Detached teeth ; British Museum (in part). 
The crowns of all the teeth are much elevated, the transversely 
ridged portion being sharply defined from the surrounding finely- 
marked area. The latter is relatively extensive, and the delicate 
rugae are mostly elongated, and concentric with the borders of the 
crown : this area is also often marked by radiating grooves. 
Form. Sf Loc. Senonian and Turonian : S.E. England, France, 
Germany. Turonian and Cenomanian: Belgium, Bohemia, and 
Russia. Cretaceous: Delaware, TT.SA. {Agassiz). 
Except where otherwise stated, the following specimens were ob¬ 
tained from undetermined horizons in the Upper or Lower Chalk :— 
4402, 4394-6. Four of the type-specimens figured by Agassiz, 
tom. cit. pi. 25 b. figs. 12, 14, 15, 18 ; Lewes, Sussex. 
Mant ell Coll. 
25775, 28336. Two teeth figured by Dixon, op. cit. ; Brighton, 
Sussex. Dixon Coll. 
28334. Sixteen naturally associated teeth and fragments in block 
of Sussex Chalk. Dixon Coll. 
28335. Three large teeth, and four smaller ; Brighton. 
Dixon Coll. 
4364, 4366-7. Three naturally associated series of teeth, one com¬ 
prising ten teeth and fragments, the second nine, and the 
third fourteen: Lewes. Mantell Coll. 
4397, 4399, 4401, 4404, 4406, 4414, 4426-7, 4430-33, 4435-43, 
4447-8, 4450. Twenty-seven detached teeth ; Lewes. 
Mantell Coll. 
49838-9. Two groups of teeth, perhaps belonging to the same indi¬ 
vidual ; Glynde, near Lewes. Capron Coll. 
P, 5389. Group of eleven naturally associated teeth, with very 
broad marginal area, aud six similar teeth (including one 
lower median), probably found with these ; Lewes. 
Presented by P. E. Coombe , Esq., 1888. 
