226 
SELACHII. 
X. Much arched narrow tooth, 
P, 2911. Type specimen of Rhamphodus dispar. J. W. Davis, 
tom. cit. p. 402, pi. li. fig. 17 ; Armagh. Enniskillen Coll. 
Most of the teeth upon which the following “ species ” are 
founded are also referable to the anterior portion of the jaws of 
Cochliodonts, but there are no examples in the Collection:— 
Helodus antiquissimus , E. von Eichwald, Leth. Ross. vol. i. (1869), 
p. 1545.—Carboniferous Limestone ; Government of Toula. 
Helodus aversus, H. Trautschold, Xouv. Mem. Soc. Imp. Xat. 
Moscou, vol. xiii. (1874), p. 268, pi. xxvi. fig. 8.—Car¬ 
boniferous Limestone ; Government of Toula, Russia. 
Helodus biformis , Newberry & Worthen, Pal. Illinois, vol. ii. 
p. 77, pi. iv. fig. 22.—Einderhook Limestone; Iowa. 
Helodus carbonarius, Newberry & Worthen, op. cit. vol. ii. p. 75, 
pi. iv. fig. 20.—Coal-Measures ; Illinois. 
Helodus compressus, Newberry & Worthen, op. cit. vol. iv. (1870), 
p. 360, pi. iii. fig. 15.—Burlington Limestone ; Illinois. 
\_JSon Newberry & Worthen, op. cit. vol. ii. p. 78, pi. v. 
fig. 1,—see Hyboclaclodus compressus, p. 29.] 
Helodus coniculus , Newberry & Worthen, op. cit. vol. ii. p, 75, 
pi. iv. fig. 19 ; J. S. Newberry, Ann, Rep. Geol. Surv. 
Indiana, 1879, p. 344.—Keokuk Limestone ; Illinois. St. 
Louis Limestone ; Indiana. Burlington Limestone; Iowa. 
Helodus consolidatus , Newberry & Worthen, op. cit. vol. ii. p. 87, 
pi. vi. figs. 1,2.—Keokuk Limestone : Missouri and Illinois. 
Helodus crenulatus, Newberry & Worthen, op. cit. vol. ii. p. 82, 
pi. v. fig. 7.—Keokuk Limestone ; Illinois. 
Helodus dens-humani, Newberry & Worthen, op. cit. vol. ii. 
p. 76, pi. iv. fig. 21.—Keokuk Limestone ; Illinois. 
Helodus denticulcitus, Newberry & Worthen, op. cit. vol. ii. p. 81, 
pi. v. fig. 6. Helodus (?) denticulcitus, St. John& Worthen, 
Pal. Illinois, vol. vi. (1875), p. 317.—Keokuk Lime¬ 
stone ; Illinois. 
Helodus elytra , Newberry & Worthen, op. cit. vol. ii. p. 78, pi. iv. 
fig. 23.—Keokuk Limestone ; Illinois. 
Helodus gibbus, J. Leidy, Trans. Amer. Phil. Soc. [2] vol. xi. 
(1857), p. 88, pi. v. fig. 18.—Carboniferous Limestone; 
Illinois. 
Helodus Icevis, J. S, Newberry, Ann. Rep. Geol. Surv. Indiana, 
1876-78 (1879), p. 343.—St. Louis Limestone; Indiana. 
Helodus Umax, Newberry & Worthen, op. cit. vol. ii. p. 80, pi. v. 
fig. 5.—Burlington Limestone ; Iowa. 
