418 BRITISH PALAZOZOIC FOSSILS. [ Bracuiopopa. 
focus.) Width of small specimen six lines, proportional length of receiving valve ;;, length of entering valve 5, 
1009 
height of area *, depth of both valves ;y,. 
The higher cardinal area, and somewhat larger and more deeply- divided ribs, and, I think, less distinctly 
punctured surface, are the only points I see to separate this species from the Permian S. cristata. 
Position and Locality.—Rare in the carboniferous limestone of Derbyshire. 
SPIRIFERA MINIMA (So27.) ? 
Ref.—Sow. Min. Con, t. 377. f. 1. 
Dese-—Rhombic ; hinge-line shorter than the width of the shell ; cardinal angles obtusely rounded ; anterior 
lateral margins slightly convex, converging towards the narrow front, which is sinuate, by the abrupt elevation 
at rather more than right angles of the front margin, into an acute sinus, about two-thirds as high as wide. 
Entering valve gently convex on the sides, arching towards the lateral margins ; profile faintly sigmoid, from the 
elevation of the narrow, rounded, or obtusely-angular mesial ridge, which is smooth ; eight or nine small, obtusely 
angular ridges on each side, extending simply nearly to the beak; beak narrow, prominent. Receiving valve 
moderately gibbous ; beak large, very much incurved, channelled from the apex to the sinus in the front margin, 
by the deep, angular, defined, smooth, mesial hollow; cardinal area rather high, triangular; surface very 
coarsely granulo-punctate under the lens. Width five and half lines, proportional length of receiving valve 7, 
length of entering valve %, width of hinge-line about ;5,, height of cardinal area ;;,, width of sinus in front 
margin #4, height thereof +, depth of entering valve =;, depth of receiving valve 2. 
This shell seems to agree with the Spirifer minimus from the same locality, figured by Sowerby ; but from 
its unridged mesial hollow seems quite distinct from the Anomites acutus of Martin, which most writers unite 
therewith. 
Position and Locality.—Rare in the lower carboniferous limestone of Derbyshire. 
SPIRIFERA OCTOPLICATA (S02.) 
Ref.—Sow. Min. Con. t. 562. f. 2 to 4. 
Dese-—Subrhomboidal, gibbous ; hinge-line slightly exceeding the width of the shell; cardinal angles 
acute ; entering valve semicircular, twice as wide as long, with regularly arched margins, moderately convex ; 
greatest depth about the middle; front margin abruptly raised into a very large rounded sinus ; mesial ridge 
very large, prominent, obtusely angulated or rounded, five narrow, simple, cord-like ribs on each side, so much 
smaller than the mid-rib that three of them, with the two intervening spaces at the margin, only equal the width 
of the mesial ridge; receiving valve gibbous, rhomboidal, from the nearly equal production of the middle of the 
front and of the beak; beak large, elevated ; mesial hollow wide, strongly defined by the lateral ribs, concave, 
produced into a rounded lobe in front to fill the sinus in the entering valve, usually with traces of two faint ribs 
towards the margin of large specimens ; cardinal area wide, triangular, its height rather less than one-fourth its 
width; entire surface sculptured with coarse, suberect, subequal, scale-like laminze of growth, and coarsely 
granulo-punctate under the lens. Width ten lines, proportional length of receiving valve 3, of entering valve = 
1003 
19 
height of cardinal area 4, greatest depth of entering valve ;;,, depth of receiving valve =. 
The great proportional size of the mesial fold, compared with the lateral ridges, easily separates this from 
the Spirifera cristata of the Permian rocks, as well as the points enumerated under that specific head. 
Position and Locality —Carboniferous limestone of Flintshire. 
SPIRIFERA ORNITHORHYNCHA (M‘Coy). PI. 3. D. fig. 27. 
Ref—Id. id. M*Coy, Synop. Carb. Foss, Irel. t. 21. fig. 2. 
Desc.—Transversely rhomboidal when young (six lines long), cruciform when old (one inch long) from the 
great prolongation of the compressed front, and abruptly contracted, nearly cylindrical sides; entering valve at 
