DEVONIAN FAUNAS. 315 
SPIRIFER MACROPLEURUS (Con.). x 
Plate XXXVII., Figs. 1-3. 
1859. Spirifer macroplewrus Hall, Pal. N. Y., vol. III., p. 202, pl. 
27, figs. 1 a—p, pl. 28, figs. 8 a—d. 
Description.—Shell large, varying from semi-circular to trans- 
versely subelliptical in outline; hinge-line varying from a little less 
than the greatest width to somewhat extended beyond the shell in 
front; cardinal extremities usually angular, varying from somewhat 
obtusely so, to acutely angular in specimens with an extended hinge- 
line. Pedicle valve strongly convex, the beak extended beyond that 
of the opposite valve, abruptly incurved over the rather large, concave 
area; the mesial sinus non-plicate, broad and deep; three broadly- 
rounded plications on each lateral slope. Brachial valve equally or 
a little less convex than the pedicle valve, with broad, prominent, 
rounded, non-plicate mesial fold; two broadly-rounded plications and 
sometimes a third smaller one on each side of the fold. The entire 
surface is marked by fine, crowded, radiating strie, and by finer con- 
centric striz, which have usually been destroyed. The shells are also 
usually marked by several more or less prominent, concentric lines of 
growth. 
The dimensions of a rather small pedicle valve are: length. 27 mm. ; 
width, 36 mm.; convexity, 10 mm. 
Remarks.—This is the largest species of Spirifer in the Helder- 
bergian faunas, and has rarely been observed in New Jersey save in 
the shaley member of the New Scotland beds, where it usually occurs 
in the form of internal casts. 
SPIRIFER PERLAMELLOSUS Hall. 
Plate XXXVII., Figs. 4-6. Plate XXXVIIL., Fig. 7. 
1859. Spirifer perlamellosus Hall, Pal. N. Y., vol. I11., p. 201, pl. 
26, figs. 1 a—t, 2 a—g. 
Description.—Shell subtrigonal to suwbsemi-circular in outline, 
greatest breadth usually along the hinge-line; cardinal extremities 
varying from rounded to mucronate. Pedicle valve strongly convex, 
