178 GLOSSARY. 
séssile, situated on a flat surface, not raised on a stalk. 
shagréened, covered with small granules. 
sexdentdta, with six teeth. 
similis, resembling (another species). 
simplex, with a single fold. 
sinistral, opposed to dextral (q.v.). 
sinistrorsa, turned to the left. 
sinuate, curved, 
siphon, a tube. 
sdlida, solid. 
solidula, somewhat solid. 
spécies, the sub-division of a genus. 
specific, belonging to a species. 
spherium, shaped like a globe. 
spire, all the whorls of a univalve except the lowest. 
spirorbis, having a circular spire. 
spléndens, shining. 
stagnadliformis, shaped like Z. stagnalis. 
stagnalis, inhabiting marshes. 
stenogyra, having compressed whorls. 
stria, fine lines. 
striated, marked with fine lines. 
stricta, compressed. 
strigdta, streaked. 
sub-dlbida, whitish. 
sub-anguléta, with a somewhat sharp angle. 
sub-apérta, somewhat open. 
