PETAtODONTIDiE. 
69 
Polyrhizodus concavus (Trautschold). 
1874. Dactylodm concavus, H. Trautschold, Nouv. Mdm. Soc. Imp. 
Nat. Moscou, toI. xiii. p. 294, pi. xxviii. 6g. 1. 
Type. Detached teeth. 
Teeth of the t 3 pical form of P. magnus, but with fewer, often 
undivided, “ rootlets.” 
Form. Loc. Carboniferous Limestone : Mjatscbkowa, Govern- 
ment of Moscow, Eussia. 
P. 4487. Two complete, one broken tooth. Purchased, 1884. 
The Collection also comprises a broken tooth (P. 227 a) of un- 
certain species, from the Carboniferous Limestone of Oreton, Shrop- 
The following species have also been founded upon detached teeth, 
but, except of P. lohatus, there are no examples in the Collection. 
To this species is probablj’ referable a broken tooth (P. 2979, 
Ennislcillen Coll.) from the St. Louis Limestone, Monroe Co., 
Illinois, U.S.A. 
Polyrhizodus amplus, St. John & Worthen, Pal. Illinois, vol. vi. 
(1875), p. 387, pi. xiii. fig. 13. — St. Louis Limestone; 
Illinois, Missouri. 
Polyrhizodus earhonarius, St. John & Worthen, tom. cit. p. 389, 
pi. X A. figs. 24, 25, pi. xiii. fig. 10. — Coal-Measures ; 
Illinois. 
Polyrhizodus (Dactylodus) concavus, St. John & Worthen (non 
Trautschold), tom. cit. p. 390, pi. xiii. figs. 17, 18. — St. 
Louis Limestone ; Illinois. 
Polyrhizodus dentatvs, Newberry & Worthen, Pal. Illinois, vol. ii. 
(1866), p. .50, pi. iii.fig. 10. — Chester Limestone ; Illinois. 
Polyrhizodus (Dactylodus) excavatus, St.John & Worthen, tom. cit. 
p. 392, pi. xiii. fig. 16.— Chester Limestone ; Illinois. 
Polyrhizodus (Dactylodus) injlexus, Newberiy & Worthen, op. cit. 
vol. ii. p. 48, pi. iii. fig. 8. — Chester Limestone ; DUnois. 
Polyrhizodus littoni, Newberry & Worthen, op. cit. vol. iv. (1870), 
p. 357, pi. iv. fig. 10. — St. Louis Limestone ; Missouri. 
Polyrhizodus (Dastylodus) hiatus, Newbeny & Worthen, op. cit. 
vol. ii. p. 47, pi. iii.fig. 7 ; Ctemptychius digitatus, J. Leidj*, 
P. 5111. Three teeth. 
P. 5490. Five specimens. 
Purchased, 1886. 
Purchased, 1888. 
shire. 
Weaver Jones Coll. 
