108 
SELACHir. 
Moscou, vol. xiii. (1874), p. 271, pi. xxvii. fig. 12 ; Helodus, 
P. Somonow & W. von MdUer, Pull. Acad. Imp. Sci. St. 
Petersb. vol. vii. (1864), p. 235, pi. i. fig. 9 .— Lower 
Carboniferous Limestone (L. G. do Koninck) or Upper 
Devonian (Trautschold) ; Government of Toula, Eussia. 
Psammodm lovianus, St. John & Worthen, torn. cit. p. 207, pL xiv. 
figs. 7-9. — Burlington Limestone ; Iowa, Illinois. 
Pmmmodus plmus, St. John & Worthen, tom. cit. p. 213, pL xvi. 
figs. 1-4, pi. xvii. figs. 1-4. — St. Louis Limestone ; Mis- 
souri, Illinois, Michigan. 
Pmmmodus reticulatus, Newberry & Worthen, tom. cit. p. 109, 
pi. xi. fig. 5 ; St. J ohn & Worthen, tom. cit. p. 224, pi. xix. 
figs. 3, 5. — Chester Limestone ; Illinois. 
Psammodus springeri, St. John & Worthen, tom. cit. p. 202, pi. xx. 
figs. 4-11. — Uj^per Burlington Limestone ; Iowa, Illinois. 
Psammodus tumulus, St. John & Worthen, tom. cit. p. 205, pi. xiv. 
figs. 1-4. — Upper Burlington Limestone ; Iowa, Illinois. 
Psammodus turgulus, St. John & Worthen, tom. cit. p. 206, pi. xv. 
Upper Burlington-Kookuk Limestone; Iowa. 
It is also uncertain w'hether the tooth described nndcr the 
0 owing name may not bo referred to a lateral position in the jaw 
of Psammodus : — 
Solenodus crenulatus, H. Trautschold, Nouv. Mem. Soc. Imp. Nat. 
Moscou, vol. xiii. (1874), p. 293, pi. xxviii. fig. H-— 
Carboniferous Limestone ; Moscow, Eussia. 
An indeterminable tooth from the Eha 3 tic of Stuttgart, certainly 
not of Psammodus, is described under the name of P. orbicularis, 
Then. (Meyer & Plieningor, Pal. Wiirttemb., 1844, p. 117, pL x. 
Genus ARCH.fflOBATIS, Newberry. 
[Ann. Now York Acad. Sci. vol. i. 1878, p. 190.] 
“ Dentition flat and pavement-like ; teeth of large size, thick and 
massive, in several rows, the different series arched and increasing 
r behind forward; under surfaces somewhat excavated 
0^0 curvature of the cartilaginous jaw; upper third of teeth 
ormed by a coat of enamel, transversely corrugated and punctate.” 
Archmobatis gigas, J. S. Newberry, foe. cit. p. 191 ; also in Ann. 
Eep. Geol. Surv. Indiana, 1879, p. 347.— St. Louis Lime- 
stone ; Greoncastle, Indiana. 
