190 
Dimensions. — Most of the specimens are about five centimetres wide, 
and three centimetres long and thick. 
Delations and Differences . — Mr. J. D. Dana rightly separated this 
from the preceding sjDecies, with which it has sometimes been confounded, 
through the similarity of their internal casts. This species differs from 
S. convolutus, by the simplicity of its folds, by the form of its dorsal ridge 
and ventral furrow ; also by the little concentric lamellse w^hich cover its 
surface. It differs from S. laminosus, McCoy, in the median rib which divides 
the mesial fold and in the groove of its dorsal ridge, also in its more robust 
cardinal process, and the greater development of its muscular impressions. 
I could not keep for it the name given by Dana, on account of the complica- 
tion that wmuld result from it. It is possible that the unnamed specimen in 
Fig. 3, PI. 3, Mr. Dana’s (PI. Ill, Fig. 3), represents merely a young 
individual of the same species. 
Horizon and Localities. — This species is nearly always associated 
with the preceding, and is found in the same strata and the same localities, 
except IVollongong and Mount Gimhela. It is rather abundant. 
Spirifer latus, F. McCoy} 
Spirvfera lata, F. McCoy, 1807, Ann. Mag. Nat. Hist., XX, p. 233, pi. 13, fig. 7. 
This is a transverse, subrhomboidal shell, nearly four times as broad as 
long, but not thick; its cardinal extremities are very acute, and its hinge area 
wide and flat. The ventral furrow is very long, and the bottom of it slightly 
angular. On each side of the ventral furrow there are from sixteen to 
eighteen narrow, rounded, lateral folds, separated from each other by shallow 
furrows. Towards the extremities of the ears these folds gradually disappear, 
and leave a nearly smooth triangular space. Except some irregular lines of 
growth, no other ornamentation is visible on the ventral valve which is the 
only one knowm to me. 
Dimensions. — ^The specimen figured by McCoy was about two and a 
half centimetres long by nine broad. The one I have described is fifteen 
millimetres long by fifty broad. 
* [Vide R. Etheridge, Junr., Geol. and Pal. tyiand., 1892, p. 229 ; A. H. Foord, Geol. Mag., 1890, VII (3), 
p. 145, t. 6.-WhS.U.J 
