3 $8 
Terms em- 
ployed in 
defcribing 
Shells: 
Opening or mouth (apertura), is that part of the ca- 
vity of the fhell which is viable. It is 
CONCHOLOGY. chap. in. 
Imeated (lineati), marked with coloured lines. Terms em- 
angular (ar.gulata), when its circumference 
has feveral angles. 
gaping (dehifcens), when one of the extremi- 
ties is wider than the other. 
— ~~ radiated (fpinofo-radiati), having the circum- ployed in 
ference bordered with Araight fpines, feparating and dc l 1 . cribin § 
divergent. 
feparated (disjun&i), having an interval be- 
tween each convolution. 
Shells. 
bimarginated (bimargirrata), when the right 
lip forms a double margin. 
* compreffed (coarftata), when it is diAindtly 
flattened. 
• femicircular (femior'oiculata), when it forms 
half a circle. 
linear (linearis), when it is narrow, and the 
length confiderably exceeds the breadth. 
longitudinal (longitudinalis), when the length 
is greater than the breadth, and the greateil dimen- 
fion is parallel to the axis of the (hell. 
orbicular (orbicularis), forming an entire 
circle. 
— Aviated (Ariata), when the cavity is marked 
with Arise, parallel to the diredlion of .the convolu- 
tions. 
tranfverfe (tranfverfa), when the breadth is 
greater than the length. 
Pillar (columella), is that part of the Aiell fituated 
within the opening, near its axis, round which the 
fpires turn. It is brought into view by dividing the 
fhell its whole length. It is 
* ■ Aattened (plana), when the furface is flat and 
fmooth. 
■ ■■ caudated (caudata), when it is lengthened be- 
yond the bafe of the Aiell. 
folded (plicata), marked with tranfverfe and 
diAindt folds. 
■ fpiral (fpiralis), proceeding from the bafe, and 
forming a fmall twiAed elongation. 
i truncated (truncata), cut tranfverfely at the 
bafe. 
Convolutions (anfradlus), are the turnings of the fpire 
round the pillar, from the opening to the bafe of 
the Aiell. They are 
bifid (bifidi), when each is divided into two 
equal parts by a furrow or fpiral line. 
. grooved (canaliculati), when the fuperior edge 
is marked with a groove. 
■ ■ ■ keel-Aiaped (carinati), when the outer turn of 
the Aiell is marked with an angle more or left 
acute. 
crowned (coronati), when the upper furface is 
bordered at a little diftance from the futures, with a 
Angle row of tubercles or fpinous feales. 
* dextral (dextri), turning from the left to the 
right. 
. . finiftral (finiftri), turning from the right to 
the left. 
lettered (feripti), marked with characters. 
■ fpinous (fpinofi), having fhert fpines on the 
furface. 
entire (fimplices), without furrows or tuber- 
cles. 
banded (fafeiati), when the furface is marked 
with broad coloured Aripes. 
lamellated (lamellati), the furface marked 
with longitudinal or tranfverfe excrefcences, and la- 
minated like membranes. 
- furrowed (fulcati), having the furface marked 
with furrows, which are always broader than Arise. 
decuffated (decuffati), when the Arise croft 
each other at right angles. 
Spire (fpira), Agnifies all the convolutions taken to- 
gether. It is 
pointed (acuta), when the convolutions join- 
ed together form an acute angle. 
flattened (deprefia), forming a flat furface. 
convex (convexa), when it is rounded, and 
the point of the bafe has little elevation. 
convex (convexo-acuta), rounded at the outer 
edge, but elevated into an acute angle. 
convex and elevated (convexo-exferta), round- 
ed at the outer edge, and elevated without forming 
an acute angle. 
convex and pointed (convexo-mUcronata), ob- 
tufe and almoA rounded at the outer edge, and ter- 
minated at the centre with a pointed elevation. 
crowned (coronata), when the outer edges of 
each convolution are accompanied with a row of 
fpines or tubercles. 
■ capitate (capitata), the convolutions united, 
forming a fwelling refembling a head. 
obtufe (obtufa), the convolutions united, form- 
ing an obtufe angle. 
— piano concave (plano-concava), the convolu- 
tions forming no elevation, but are flightly grooved. 
pyramidal (pyramidata), of a conical form. 
Sutures (futurae), fignify the place of junction of the 
different convolutions, forming a fpiral line. They 
are 
• grooved (candliculatse), when they are fo deep 
as to form a fmall canal. 
— ■ notched (crenulatae), when the points of con- 
tact are marked with notches. 
double (duplicate), accompanied with two 
Arise, which run parallel. 
effaced (obfoletse), when the place of junftion 
is not perceptible. 
Siphon (Apho), is a fmall canal Atuated in the inter- 
nal part of the Aiell of the nautili, which penetrates 
into the divifions of which it is eompofed. It is 
central (centralis), when it is fituated in the 
middle of the divifions. 
lateral (lateralis), fituated at one fide. 
— oblique (obliquus), cutting the axis of the di- 
vifions obliquely. 
Veins (varices), are elevations or ribs, running in the 
direction of the length of the Aiell, formed by the 
junction of the different additions which the Aiell 
has received. They cut the convolutions of the 
fpire tranfverfely. They are 
continued (continuatae), proceeding from the 
bafe of the fpire to the convolution at the opening, 
without interruption. 
■ ■ fpinous (fpinofae), furniAied with Arong fpines. 
.. ■ — interrupted (decuffatse), not correfponding with 
the different convolutions. 
CHAP* * 
