308 
SELACmi. 
1868. Stropkodus ratisbonensts, C. W. vou Giimbol, Oeogn. Ilesclireib. 
Ostbay. Grenzgeb. (Googn. Beschreib. Konigr. Bay., pt. ii.), p- 762, 
woodc. ' 
1860. Strophodtis medius, 11. Owen, Geol. Mag. vol. vi. p. 103, pi. vii. 
1876. Asteracmdhux ornalissimus, K. Fricke, Palroontogr. vol. xxii. 
p. 387, pi. xxii. fig. 4. 
1875. Asteracanthua preusii, K. Fricke, tom. cit. p. 388, pi. xxii. fig. !• 
1876. Strophodm reticulatng, K. Fricke, tom. cit. p. 391, pi. xxi. fig. 16. 
1888. Aateracanthus ornaimimtta, var. ficUonemu, A. S. Woodward, 
Ann. Mag. Nat. Hist. [6] vol. ii. p. 3!16, pi. xii. 
Type. Dorsal fin-spine; Paris Museum of Natural History. 
The type species, of very largo size, the oxscrtcd portion of the 
dorsal fin-spine sometimes attaining a length of 0-48. 
Dorsal fiti-spines robust, ornamented by relatively largo, rounded 
or elongated, stellate tubercles, of unequal size, generally arranged 
in longitudinal series, sometimes very irregular, rarely in part 
fused into short ridges ; anterior face rounded, sometimes keeled ; 
posterior face raised into a median longitudinal ridge, with two 
series of largo denticles. 
Crowns of the small hindermost teeth, and those of series in.) 
IV. gently rounded, coarsely reticulated, without longitudinal keel, 
but the most jirominent superficial markings often becoming in part 
nearly parallel and transverse ; teeth of series i., ii. considerably 
elevated, prominently keeled in the (? lower) jaw, less so in the 
opposite, the superficial ornament partly reticulate, but the principal 
markings more or less transverse and radiating or parallel. 
That the dentition named Stropliodna reticulutujt by Agassiz 
pertains to this species, is proved by specimens from the Oxford 
Clay, described by the present writer, loc. cit. ; and the nearly 
complete dentition of one jaw is made known by the so-called 
S. medius. 
Form. ^ Loc. Lower Oolite : Normandy. Middle Oolite: 8 . England. 
Upper Oolite: 8 . England, N. France, W. Switzerland, and N. 
and S.W. Germany. 
(i.) Dorsal Fin-spines. 
P. 586. Type specimen of A. papillosus described by Egerton, loc. 
cit. ; Great Oolite, Caen, Normandy. Eyerton Coll. 
32731-2. Greater portion of a smaller spine, with very largo 
posterior denticles, and the tubercular ornament finer than 
in the last ; also a portion of a spine of similar size, with 
relatively larger tubercles ; Caen. Tesson Coll- 
^ This species i® described as obtained from the Oreensand; biitDr. K. A* 
von Zittel informs the present writer that it was moat probably obtained from 
tlie underlying Juraaeic rocks. 
