C0CHLI0D0NTID2E. 
215 
(ii.) Inrollecl variety (? lower jaw), shown by Agassiz , tom. cit. p]. xiv. 
figs. 32, 33, and by Davis, tom. cit. pi. liii. fig. 18. 
P. 2438. Type specimen : Bristol. Enniskillen Coll. 
P. 2440 a. Imperfect dental plate ; Bristol. Enniskillen Coll. 
20575 a. Imperfect dental plate; Bristol. Purchased, 1845. 
P. 1478 b. Two specimens ; Black Bock, Bristol. Egerton Coll. 
40329. Perfect, though abraded, specimen ; Clevedon, Somersetshire. 
Purchased, 1867. 
P. 1478 C. Similar specimen : Hook Point, Wexford. Egerton Coll. 
P. 5351. Imperfect specimen shown of the natural size in PI. I. 
fig. 21 ; Ticknall, near Melbourne, South Derbyshire. 
Wilson Coll. 
P. 5350. Two fragments of worn dental plates, probably of this 
species ; Ticknall. Wilson Coll. 
The following species have also been founded upon detached 
dental plates, but there are no examples in the Collection:— 
Deltoptychius eccpansus, St. John & Worthen, Pal. Illinois, vol. vii. 
(1883), p. 98, pi. v. figs. 9-11 (also figs. 12, 13, Streblo- 
tZws-plates).—St. Louis Limestone; Illinois, Iowa, Missouri. 
Deltopty chius niticlus, St. John & Worthen, tom. cit. p. 99, pi. v. 
fig. 16 : Cochliodus niticlus, J. Leidy, Trans, imer. Phil. 
Soc. [2] vol. xi. (1857), p. 87, pi. v. fig. 2.—Chester 
Limestone; Illinois. 
Deltopty chius primus, St. John & Worthen, tom. cit. p. 93, pi. v. 
fig. 6 (also figs. 7, 8, Strebloclus- plates).—Upper Burling¬ 
ton Limestone ; Iowa. 
Deltoptychius ivachsmuthi, St. John & Worthen, tom. cit. p. 93. 
pi. y. figs. 1, 2 (also figs. 3-5, Strebloclus-^lsites). — Keokuk 
Limestone ; Illinois, Iowa, and Missouri. 
Deltoptychius vcirsouviensis, St. John & Worthen, tom. cit. p. 96, 
pi. y. fig. II (also fig. 15, Strebloclus- plate).—Warsaw 
Limestone; Illinois. 
As already remarked (p. 205), dental plates of the form here re¬ 
garded as Deltoptychius are described by St. John and Worthen as 
Poecilodus vortheni and P. springeri. The Belgian tooth named 
