544 BRITISH PALAZOZOIC FOSSILS. [GasrEropopa. 
to this species, as it lengthens much with age, but his figure and description do not seem to agree with it. Coll. 
Portlock’s figure 6 is a good representation of the middle age when the body-whorl is becoming concave ; 
his figure 7 is of a younger specimen. 
NATICOPSIS SPIRATA (Sow. Sp.) 
Ref. and Syn.= Nerita spirata Sow. Min. Con. t. 463. f.1, 2. 
Dese.—Semiglobose, of three very rapidly enlarging whorls; turns of the spire small, slender, rounded, 
prominent; apical angle about 130°; body-whorl very convex in the middle, flattened or widely concave on the 
upper or sutural quarter in old specimens ; mouth very large; columella much arched, narrow; lines of growth 
fine, irregular, imbricating, inconspicuous, not much stronger near the sutures than elsewhere. Length and 
width equal, of large specimen thirteen lines, proportional length of mouth or last whorl “, width of mouth &, 
space between last and penultimate sutures ;;;. 
The little, sharply-defined, prominent spire of tumid whorls, and the surface being nearly smooth from the 
inconspicuous strize of growth, as well as less expanded mouth, separate this species from 1. ampliata, to which 
it is most allied. The strize are not connected into sharp regular plicze near the suture, as in several species of 
the genus, and Sowerby’s words do not bear that interpretation, as subsequent writers seem to think: he says, 
‘the lines of growth are sometimes rather conspicuous on the flat part of the whorls, in other parts they are 
very slight;” which is a proper statement of the characters, as most usually the strie are quite evanescent on 
the sutural parts of the whorls. 
Position and Locality.—Rare in the lower carboniferous limestone of Derbyshire; not very uncommon in 
the lower carboniferous limestone of the Isle of Man. 
NATICOPSIS VARIATA (Phill. Sp.) 
Ref. and Syn. = Natica variata Phill. Geol. York. Vol. II. t. 14. f. 26, 27. 
Desc.—Obliquely oval, globose ; spire very small, slightly pointed, of two and a half gently convex whorls; 
sutures slightly concave and imbricating ; surface with extremely minute, (fifteen or sixteen in one line), slightly 
undulating, spiral striee, obscure on the spire; crossed by slightly larger, moderately oblique lines of growth, 
deepening near the sutures into sharp, regular, slightly coarser plicee; pillar-lip as in the generic character. 
Length and width of large specimen seven lines, proportional length of last whorl 4, space between last and 
penultimate suture =. 
This is a very rare species, much resembling the young of JV. plicistria, but with the plicistriation of the 
sutures finer, and easily distinguished from it and all other species by the close, minute, spiral lineation of the 
surface. This spiral striation is supposed by M. de Koninck to be a deceptive appearance due to a 
spathose condition of the shell; but I agree with Mr Phillips that it is a true sculpturing, and further, I suspect 
that the large shell figured and described under this name by M. de Koninck is some different species, both 
from its great size, more numerous whorls, and want of the characteristic lineation. 
Position and Locality—Two well-marked specimens from the dark carboniferous limestone of Lowick, 
Northumberland. 
Genus. LOXONEMA (Piill.) 
Gen. Char.—Shell narrow, very long, spire of very numerous convex whorls, apex simply pointed ; body- 
whorl small; aperture elongate, oblong, indented by the body-whorl, much longer than wide, prolonged in front 
into a rounded lobe; lips disunited behind; outer lip oblique, with a rounded backward sinus at the sutures, 
conyex in the middle; columella slightly thickened; no umbilicus; surface of whorls crossed by close, oblique, 
inversely sigmoid, thread-like ridges or lines of growth. 
