198 
8ELACHII. 
Deltodus rugosus, sp. nov. 
Type. Upper and lower dental plates, shown in I’l. VI. figs. 21, 
22 . ' 
A very small species, the maximum transverse measurement of 
the supposed lower posterior dental plate being about O'Oll. Trans- 
verse ridges and furrows of the dental crown fine, not always con- 
tinuous, more or less w'avy. Posterior “ lower ” dental plate notably 
elongated in an antoro-posterior direction, the gently rounded 
coronal elevation extending from the outer to the inner margin not 
immediately adjoining the antcro-lateral border. 
Farm. ^ Loc. Carboniferous Limestone : Shropshire. 
42186, 36193. Type specimens shown, of twice the natural size, in 
ri. VI. figs. 21, 22, the first being an “ upper ” dental 
plate, the second a “ lower ” ; Oreton. 
Raugh Coll., and Purchased, 18G1. 
42186 a. Imperfect “ upper ” dental plate ; Oreton. Baugh Coll. 
42186 b, 42225. Four imperfect “ lower ” dental plates ; Oreton. 
Baugh Coll. 
Deltodus concha (Trautschold). 
1874. Poscilodus oonchn, 11. Trautschold, MtSni. Soc. Imp. Nat. Moscou, 
vol. xiii. p. 290, pi. xxviii. fig. (i, pi. xxix. fig. 10. 
1874. VcRcilodii'i Umhatm, II. Trautschold, tom. cit. p. 290, pi. xxviii. 
fig. 7. 
Type. Detached tooth. 
A comparatively small species, the maximum transverse measure- 
ment of the supposed lower posterior dental plate being about O'OIG. 
Transverse ridges and furrows of the dental crown few, largo, 
rounded. Posterior “ lower ” dental plate (“ Pcecilodus limhatus ) 
slightly elongated antoro-posteriorly, the prominent elevation ex- 
tending from the outer to the inner margin very broad, gently 
rounded, immediately adjoining the antero-lateral margin. Anterior 
“lower” dental plate Pmihdus concha") rapidly widening 
inwardly. 
dorm. ^ Loe. Carboniferous Limestone : Government of Moscow, 
Eussia. 
P. 5115. Three anterior dental plates ; Mjatschkowa. 
Purchased, 1886. 
