196 
Melations and Differences. — This species bears a great resemblance 
to S. subcuspidatus, J. Hall ; nevertheless it differs in several important 
characteristics. Tirst, its length is less ; then, the beak of the ventral valve 
is much more recurved ; and again, the angle of the apes is about 130°, while 
that of S. subcuspidatus is only about 110°. 
Horizon and Localities. — This species was found in the dolomite of 
Glenwilliam and Colocolo. 
SPIEIPERINA. 
Spiriferina cristata, V . Schlotheim. 
Terebratulites cristatus, 
Spirifer octopUcatus, 
,, cristatus, 
53 33 
33 33 
Spirifera octoplicata, 
Spirifer octopUcatus, 
33 33 
Von Sclilotheim, 1816, Scliriften K. Baier, Akacl. Wissen. Miia- 
clien, VI, pi. 13, fig. 3. 
J. Sowerby, 1827, Min. Concli., VI, p. 119, pi. 562, fig. 2, 3,4. 
L. V. Buch, 1837, Ileber Delthyris, p. 39. 
Idem, 1840, Mem. Soc. Gleol. France, IV, p. 185, pi. 8, fig. 9. 
L.-G. de Koninck, 1843, Descr. Anim. Foss. Terr. Carb. Belg., p. 
240, pi. 15, fig. 5. 
F. McCoy, 1844, Synoj). Carb. Foss. Ireland, p. 133. 
A. d’Orbigny, 1850, Prod. Pal., I, p. 125. 
L.-G. de Koninck, 1851, Descr. Anim. Foss. (Suppl.), p. 658. 
Spirifcra octoplicata, F. McCoy, 1855, Brit. Pal. Foss., p. 418. 
Spiriferina cristata, var. octoplicata, T. Davidson, 1857, Mon. Brit. Carb. Brack., pp. 38 
and 267, f)!. 7, fig. 37-47, and pi. 54, fig. 10, 12. 
Idem, 1860, Mon. Carb. Brack. Scotland, p. 23, pi. 1, fig. 36-38. 
J. W. Dawson, 1868, Acad. GeoL, p. 292, fig. 90. 
This is a small, transverse, sub-rhoniboidal shell, sometimes a little 
gibbous, having its greatest breadth at the hinge line. Its cardinal angles are 
often slightly rounded at their extremities. The ventral valve is scaicely 
deeper than the dorsal valve; its beak is small and very little lecurved , its 
hinge area is concave, triangular, and rather variable in length ; its deltoid 
fissure is partly recovered by a pseudo-deltidium ; its ventral furrow is deep, 
acute at the bottom, and usually simple. The dorsal ridge is generally formed 
of a single angular fold rather more pronounced than the adjacent folds, but 
