154 DEVONIAN FAUNA. 
in size, and the much larger number of major radiating ribs. I should be inclined 
to class them together, but that I have met with no intermediate specimens 
whatever, though neither form is rare. 
The hinge-area of the ventral valve seems marked by fine oblique lines, and that 
of the dorsal valve by numerous short, perpendicular, tooth-like ridges. It is to 
be noted that the transverse ruge are frequently more pronounced than is 
indicated by Davidson’s figures. 
Stropheodonta Patersoni, Hall,‘ is marked with similar wrinkles, and has inter- 
mediate radiations, but differs in other respects. 
VIII. Family.—Provvuctiva, King, 1846. 
1. Genus.—Propucrgetia, Hall, 1867. 
Hall has separated under this name the Devonian species of Productus as 
having cardinal areas and articular processes of the valves. P. subaculeata was 
taken as the type of the genus. It is regarded as a genus or sub-genus by 
(ihlert and by Zittel, but it was not adopted by Davidson. I have not myself 
been able to form any independent opinion on the question. 
1. PRopuoTELLA suBACULEATA, Murchison, sp. 
1840. Propuctus suBacuLEaTUs, Murchison. Bull. Soc. Géol. Fr., vol. xi, p. 
255, pl. ii, fig. 9. 
1840. Leprmna FraGaRia, Sowerby. Geol. Trans., ser. 2, vol.v, pt. 3, pl. lvi, fig. 5 
(only). 
1865. Propucrus suBacuLEaATUS, Davidson. Brit. Foss. Brach., vol. iu, pt. 6, 
p- 99, pl. xx, figs. 1, 2. 
1867. PropucTELLA suBacuLEaTA? Hall. Pal. N. Y., vol. iv, pt. 1, p. 154, pl. 
xxiil, figs. 4, 5. 
? 1867. _ sPpInuULICosTA. Ibid., p. 160, pl. xxiii, figs. 25—34. 
1867. — SHUMARDIANA. Ibid., p. 157, pl. xxiii, figs. 6—8, 35—387. 
? 1867. — mruncata. Ibid., p. 160, pl. xxiii, figs. 12—24. 
1883. Propucrus suBACULEATUS, Kayser. In Richtofen’s China, vol. iv, p. 93, 
pl. xiii, fig. 5. 
! 1867, Hall, ‘Pal. N. Y.,’ vol. iv, pt. 1, p. 89, pl.. xiii, figs. 1—5. 
