PETALODONTID^. 
49 
Phil. Soc. [2] vol. xi. (1857), p. 89, pi. v. figs. 24-26. — 
Lower Carboniferous, Illinois ; and St. Louis Limestone, 
Missouri. 
Choviatodug lamelliformis, J. W. Davis, Quart. Journ. Geol. Soc. 
vol. xl. (1884), p. 625, pi. xxvii. fig. 23. — Yoredale Rocks ; 
'Wensleydale, Yorkshire. 
Chomatodus loriformis, Newberry & Worthen, oj>. eit. vol. ii. p. 58, 
pi. iii. fig. 19. — ^Keokuk Limestone ; Illinois. 
Chomatodus molaris, Newberry & Worthen, op. cit. vol. ii. p. 56, 
pi. iii. fig. 17. — Keokuk Limestone ; Dlinois. 
Chomatodus multipUcatus, Newberry & Worthen, op. cit. vol. ii. 
p. 57, pi. iii. fig. 18. — Burlington Limestone ; Iowa. ? Also 
Tanaodus multipUcatus, L. G. de Koninok, Faune Calc. 
Carbf. Belg. pt. i. 1878, p. 53, pi. vi. fig.s. 10, 11. — Lower 
Carboniferous Limestone ; Tournai. 
Chvniatodus parallelus, St. John & Worthen, op. cit. vol. vi. p. 358, 
pi. x.A. figs. 3, 4. — Warsaw Beds; Dlinois, Missouri. 
Chomatodus pusillus, Newberry & Worthen, op. eit. vol. ii. p. 53, 
pi. iii. fig. 14. — Keokuk Limestone ; Illinois. 
Chomatodus sareululus, Newberry & W orthen, op. cit. vol. iv. p. 356, 
pi. ii. fig. 8. — Burlington Limestone ; Iowa. 
The genus Litgtxlus, St. John & Worthen (op. cit. vol. vi. 1875, 
p. 363), is difficultly definable from Petalodus. Four species are 
described — L. eurtus (tom. cit. p. 364, pi. x. a. figs. 20-22), L. selluli- 
formis (tom. eit. p. 366, pi. x.A. fig. 16), L. serratus (tom. cit. p. 365, 
pi. x.A. figs. 17-19), and L. affinis (J. S. Newberry, Ann. Rep. Geol. 
Surv. Indiana. 1879, p. 343). The first and third are from the 
Upper Burlington Limestone, Illinois and Iowa; the second and 
fourth from the Upper St. Louis Limestone, Illinois and Missouri. 
Closely allied also is the genus Calopodvs, St. John & Worthen, 
represented by the single species C. apicalis, St. J. & W. (Pal. 111. 
vol. vi. 1875, p. 403, pi. xii. figs. 16, 17), from the Middle Coal- 
Measures of Iowa. 
Genus CTENOPTYCHIUS, Agassiz. 
[Rech. Poiss. Foss. vol. iii. 1838, p. 99.] 
Syn. Ctenopetalus, J. W. Davis (ex Agass. MSS.), Arm. & Mag. Nat. 
Hist. [5] vol. viii. 1881, p. 426. 
Harpacodus, J. W. Davis (&v Agass. MSS.), loc. eit. p. 426. 
Serratodus, L. G. de Koninck, Faune Calc. Carbf. Belg. pt. i. 
1878, p. 53. 
PeripristU, 0. St. John, Proc. Amer. Phil. Soc. vol, xi. 1870, 
p. 434. 
B 
