COCHLIODONTIDiE. 
199 
Deltodus occidentalis (Leidy). 
1857. Cochliodus occidentalis, J. Leidy, Trans. Amer. Phil. Soc. [2] 
yoI. xi. p. 88, pi. v. figs. 3-16. 
1866.. Deltodus stellatus, Newberry & Worthen, Pal. Illinois, vol. ii. 
p. 97, pi. ix. figs. 2, 3. 
1883. Deltodus occidentalis P, St. John & Worthen, op. cit. vol. vii. 
p. 150, pi. ix. figs. 9, 10. 
Type. Detached dental plates. 
Transverse coronal folds, when present, broad and faintly marked, 
but generally absent. “ Lower ” posterior dental plate obliquely 
twisted, gently arched, with the outer apex closely inrolled; 
anterior coronal elevation extending from the outer to the inner 
margin broad, unequally divided by a faint angulation along its 
highest part. 
St. John and Worthen describe the supposed lower median dental 
plate and the upper posterior dental plate of this species. 
Form, df Loc. St. Louis, Warsaw, and Keokuk Limestones (Lower 
Carboniferous): Illinois, U.S.A. 
P. 2453. Two abraded examples; Keokuk Limestone, Warsaw, 
Illinois. Enniskillen Coll. 
Deltodus spatulatus* Newberry & Worthen. 
1866. Deltodus spatulatus , Newberry & Worthen, Pal. Illinois, vol. ii. 
p. 100, pi. ix. fig. 7. 
1879. Deltodus spatulatus, J. S. Newberry, Ann. Rep. Geol. Surv. 
Indiana, 1876-78, p. 346. 
Type. (?) u Upper ” dental plates. 
Supposed upper dental plate obliquely spatulate in outline, the 
broader end having rounded angles; anterior long coronal promi¬ 
nence gently angulated; unabraded coronal surface with only faint 
transverse parallel furrows. 
Form. Log. Burlington and Keokuk Limestones (Lower Car¬ 
boniferous) : Illinois and Indiana, U.S.A. 
P. 2452. Two imperfect specimens; Burlington Limestone, Quincy, 
Tllinois, Enniskillen Coll. 
The following species have also been founded upon detached 
teeth, but there are no examples in the Collection :— 
Deltodus alatus , Newberry & Worthen, Pal. Illinois, vol. iv. 
(1870), p. 368, pi. ii. fig. 6. —Keokuk Limestone; Illinois. 
Deltodus aliformis, J. W. Davis, Trans. Roy. Dublin Soc. [2] 
vol. i. (1883), p. 431, pi. liii. fig. 12: Poecilodus aliformis , 
