THE NATURAL HISTORY SURVEY. 389 



Serrated. Notched, like the teeth on a saw. 



Serriform. In the form of series. 



Sessile. Attached without a stem, as the eyes in some water snails. 



Shouldered. Ridged, as the whorls in some snails (pi. xxxv, fig. 9). 



Sigmoid. Shaped like the letter S. 



Siliceous. Made up of silex. 



Sinistral. Having the aperture on the left side (pi. xxxiv, fig. 3). 



Sinuous. Curved in and out, as the edge of some bivalves and the lips 

 of some snails (pi. vii, fig. 7; pi. xxxii, fip. 6). 



Spatulate. In the form of a spatula, a flat-bladed instrument used by 

 druggists in pulverizing drugs. 



Spherical. Shaped like a sphere. 



Spiral. Wound about a central cavity, as the whorls of snails. 



Striated. Marked by lines or striae. 



Subangulated. Moderately angled. 



Subcarinated. Moderately carinated. 



Subcentral. Not quite in the center. 



Subcircular. Not quite circular. 



Subconical. Moderately conical. 



Subcylindrical. Moderately cylindrical. 



Subequal. Not quite equal. 



Subexcavated. A little excavated. 



Subfusiform. Moderately fusiform. 



Subglobose. Moderately globose. 



Subglobular. Moderately globular. 



Subhyaline. Moderately glassy. 



Subimperforate. Not much perforated. 



Suboblong. Moderately oblong. 



Subobsolete. Almost disappearing. 



Subovate. Nearly ovate. 



Subparallel. Almost parallel. 



Subperforated. Almost perforated. 



Subquadrate. Almost four-sided. 



Subreflected. Moderately turned back. 



Subrotund. Moderately round. 



Subspiral. Moderately spiral. 



Subtriangulate. Moderately or almost triangular. 



Subtrigonal. Moderately three-angled. 



Subtruncate. Moderately cut off. 



Subumbilicated. Moderately umbilicated. 



Sulcated. Grooved. 



Sulcus. A longitudinal furrow. 



Superanal. Above the anus. 



Supra-peripheral. Above the periphery. 



Symmetrical. Alike on both sides or uniform in all parts. 



Symphynote. Having the posterio-dorsal portion of the shell flat- 

 tened and produced, as in Symphynota complanata. 



Terrestrial. Living on the land. 

 Testaceous. Composed of shelly matter. 



