COCIILIOUONTin.li. 
185 
Psephodus simple.v, J. W. Davis, Geol. Mag. [11] vol. iii. p. 151, 
figs. 1, 2.— Carboniferous Limestone; Derb^vshire. 
(^1) Psephodus symtnetricus, St. John & Worthen, oy». cit. vol. vii. 
p. 71, pi. i. figs. 6, 7. — Kinderhook Limestone ; Iowa. 
The so-caUed P. lumdatus, St. John & Wortlien {op. cit. vol. vii. 
p. 74, pi. ii. fig. 4), from the Chester Limestone of Illinois, appears 
to be founded upon a specifically indeterminable anterior tooth of 
Psephodus; and very doubtful, also, is 7^.(?) reikidatus, St. John & 
M orthcn {op. cil. vol. vi. 1875, p. 417, pi. vi. figs. 19-24), from the 
Kinderhook Limestone of Iowa. Other evidence of the genus, from 
the Lower Carboniferous of Russia, has been described and figured 
by Semenov and Mbller, Bull. Acad. Imp. Sci. St. Petersb. vol. vii. 
(1864), p. 2134, pi. i. fig. 10 (? and other figs.) ; and a doubtful tooth 
from the Salt Range, India, is named P. dejiressus, W. AVaagon, Joe. 
cit. p. 75, pi. vii. fig. 4. 
A tooth from the Keokuk Limestone of Illinois, very suggestive 
of a broken example of Psephodus, has also been described under 
the name of Trigonodus minor, Kewberry & Wortben (Pal. Illinois, 
vol. ii. 1866, p. 1 12, pi. xi. fig. 7 ) ; and a second example is recorded 
from the St. Louis Limestone of Indiana (J. S. Kewberry, Ann. Hep. 
Geol. Surv. Indiana, 1876-78 (1879), p. 1341). 
Genus SANDALODUS, Newberry & Wortben. 
[Pal. Illinois, vol. ii. 1866, p. 102.] 
Sy n. Triyonodus, Newberry & Woi*lhen, tom. cit. 1 866, p. 1 1 1 (in pwt). 
Vaticinodus, St. Jolm & Wortben, Pal. Illinois, vol. vii. 1880, p. 80. 
Orthopteurodus, St. John & Wortben, tom. cit. p. 190 (in part). 
Dental plates of “upper” jaw triangular in outline, slightly 
inrolled, having the antero- and postero-lateral borders each consi- 
derably longer than the inner margin. Coron<il contour undulating 
in transverse section, the anterior portion raised into a low rounded 
longitudinal ridge, passing into a slightly hollowed posterior area. 
Dental plates of “ lower ” jaw subtriangular or club-shaped in out- 
line, with one or two pointed extremities, considerably inrolled, and 
the longer axis approximately in an antero-posterior direction ; 
coronal ridges and hollows few or absent. 
Sandalodus morrisii, Davis. 
]i^62. Dcltodus sp., Morris & Roberts, Quart. Journ. Ceol. Soc. 
vol. xviii. p. 105, pi. iii. figs. 1 .3. 
(H) lf^02. Dcltodus .sp., Morris ik Roberts, toe. cil. pi. iii. lig. 1. 
