STOMATIA. 101 
Serputa, Auct. which makes a groove for itself in the surface 
of univalve shells. Serpula spirorbis, var. Dillwyn, Fig. 8. 
SPIROLI'NA. Lam. A genus of microscopic Foraminifera. 
SPIROLOCULI'NA. D’Orb. A genus of microscopic Forami- 
nifera. 
SPIROR’BIS. Lam. A genus composed of species of Surputa, 
Auct. which are coiled round in a spiral disc, like a snake at 
rest. S. nautiloides, fig. 5, is the common little white shell 
found upon the shell of lobsters. 
SPYRULA. (Spira, a winding compass.) Fam. Lituolata, Lam. 
Lituacea, Bl. Deser. Convolute, smooth, symmetrical, discoid, 
with parallel, unconnected whorls, divided into numerous cham- 
bers by transverse septa; siphon continuous. Obs. This pretty 
little shell is partly internal, only a part of it being visible when 
on the animal. Fig. 471. 
SPI'SULA. Gray. A genus composed of Mactra fragilis and 
other similar species which have the ligament sub-external, 
marginal, not separate from the cartilage; with the posterior 
lateral teeth double and single. M. fragilis, fig. 80. 
SPON'DYLUS. Lam. (A shell-fish, Ancients.) Fam. Pectenides. 
Lam. Sub-ostracea,Bl. Descr. In-equivalve. sub-equilateral, ir- 
regularly foliaceous and spinose, auriculated, denticulated at the 
margins, attached by the lower and deeper valve; hinge recti- 
linear, with two prominent teeth in each valve, locking into 
corresponding cavities on the opposite valve; umbones sepa- 
rated by a broad, elongated triangular disc in the lower valve ; 
ligament contained in a groove, dividing the triangular area in 
the centre; muscular impressions, one in éach valve, sub-central, 
sub-orbicular. Obs. This genus is remarkable for the richness 
and beauty of the spines and foliations, which adorn the ex- 
ternal surface of most of the species, the splendid colours by 
which many of them are varied, and the natural groupings 
formed by their attachment to each other. Fig. 177, and Fron- 
tispiece. 
SPOR/ULUS. Montf. <A genus of microscopic Foraminifera. 
SQUA’MOSE. (Squama, a scale.) Scaly, covered with scales, as 
the pedicle of Pollicipes Mitellus. Fig. 37.* 
STOMATEL'LA. v. Stomatta. 
STOMA’TIA. Lam. (cropa, stoma, mouth.) Fam. Macrostomata. 
Lam. Deser. Sub-orbicular, oblong, auriform, variegated with- 
out, iridescent within; spire depressed; aperture entire, very 
wide, oblique; peritreme uninterrupted. Obs. This genus is 
known from Haliotis, by being destitute of the series of holes; 
is distinguished from Sigaretus, by the substance of the shell, 
the latter being internal, never pearly. Our description includes 
Sromatenia, Lam. The Stomatie are marine, and belong to 
the East Indies and New Holland. Fig. 335, S. Phymotis. 
