OF CONCHOLOGY. 103 



Subgenus Cbntronella, Bill. 



Centronella, Billinors, Can. Nat. iv. 1859, p. 131. A. J. Sci. 

 vol. 36, p. 237. 



Shell resembling Terebratida, but with the mesial sinuation of 

 the loop prolonged toward the neural valve, in the shape of a 

 thin lamina. 



Ti/pe. Centronella glans-fagea (Rail sp.), Bill., in Can. Nat. 

 1859, p. 131, fig. 1 to 5, and Am. Journ. Sci. xxxvi, p. 



237, fig. 8. 



Fossil in the Devonian of Canada. Plate vi, fig. 8. 



? Subgenus Epithyris, King. 



Epitliyris, King (not Phillips), Perm. Foss. p. 146, 1850. 

 Semimda, M'Coy, Br. Pal. Foss. 1855 [not ^= Se77iinula, 



M'Coy, 1841). 

 Dielasma, King, Proc. Dub. Univ. Zool. and Bot. Assoc, vol. 



i, 1859, p. 260. 



Shell with lamellre supporting the teeth of the neural valve, a 

 short loop as in Terebratida, but more abruptly sinuated an- 

 teriorly, and with the central lamina of the hinge plate, in the 

 hnemal valve, produced in the form of a mason's trowel, and sup- 

 ported beneath by a mesial septum. 



Type. Epithyris elongata, King, = Terebratidites elongatus, 

 Schloth. Fossil, Permian. Plate viii, fig. 7, after Da- 

 vidson. 



Mr. Davidson's figure in the Permian Brachiopoda represents 

 the hinge lamina as produced almost as far as the loop, and very 

 prominent ; those of Prof. King in the Permian Foss. show little 

 more than may be observed in various species of different genera 

 in this family. If the last-named figures be correct, the group 

 is hardly of subgeneric value. 



Epithyris of Phillips (Pal. Foss. 1841, p. 55) was not suffi- 

 ciently characterized, and no type was mentioned. Hence the 

 name was still available, as it represented nothing. Prof. King 

 applied it to this species and others allied to it, naming and 

 figuring the species above mentioned as his type. In 1844 Prof. 

 M'Coy had given the name Seminula to a group belonging to the 



