194 
Spirifer tasmaniensis, J. Morris} 
PI. IX, Pig. 7. 
Spirifera rotundcita^ G-. B. Sowerbj, 1841, In Darwin’s Geol. Obs. Vole. Islands, p. 1.59 
(non J. Sowerby). 
Spirifer Tcisinciniensis, J. Morris, 1845, In Strzelecki’s Pliys. Descr. N. 8. Wales and D. 
Land, p. 280, pi. 15, fig 3, 4. 
Spirifertt ,, P. M‘Coy, 1847, Ann. Mag. Nat. Hist.. XX, p. 233. 
Spirifer Tasmcinni, L. v. Bueb, 1847, Ueber Spirifer Keilhavii, p. 11, fig. 3. 
This is a moderate-sized, transversely oval shell. Its ventral valve is 
rather convex, and deeper than the dorsal valve ; its beak is strongly recurved, 
partly covering the deltoid fissure ; the hinge area is flat, with suhparallel 
edges, extending across the whole breadth of the valve ; the ventral furrow 
is evenly hollowed into the form of a canal, and ornamented with from eight 
to ten small, simple, longitudinal ribs multiplying by insertion on each side 
of the furrow. The dorsal valve, the lateral portions of which are slightly 
depressed, has a very prominent dorsal ridge, ornamented with ribs exactly 
like those of the ventral furrow. Some broader, radiating, lateral folds, from 
ten to twelve in number, ornament both valves ; these folds, simple at first, 
bifurcate or trifurcate at some distance from their origin, and at variable 
distances are broken by concentric lines of growth, making them appear more 
or less imbricated. The edge is sharp ; the test rather thin, nacreous, and 
fibrous in substance. The spiral supports, traces of which remain on the 
internal casts, have the form of an elongated cone produced by eighteen or 
twenty turns of the lamella. 
Dimensions. — These have been taken from an almost perfect specimen; 
length thirty-five, breadth forty-eight, and thickness twenty-two millimetres. 
Relations and Differences.~l}xom the form of its lateral folds, 
this species strongly resembles S. diipUcicosta, Phillips, also certain varieties 
of S. striatus, Martin ; but it differs from the first by the form and length 
of its hinge-area, and from the second by the very distinct boundaries of its 
ventral furrow and dorsal ridge, also by the shape and regularity of the folds 
covering tlie furrow and ridge. 
' [Spiriferu tasmaniends. R. Etheridge, Junr. , Geol. and Pal. Q’land., 1892, p. 232, t. 10, f. 1, ? f. 15. — 
W.S.D.] 
