Sac, a cavity or pouch.
Sa' crum, a composite bone formed by the union of vertebræ in the region of hips.
Scap' u la, the shoulder-blade.
Sep' tum (pl. sep' ta), a wall or partition between two cavities.
Se' ta (pl. se' tae), small bristles or stiff hairs.
Sex' u al, pertaining to sex.
Si' nus ve no' sus, an enlargement of the termination of the large veins.
Si' phon, a tube-like organ.
So' mites, the serial segments or rings composing the bodies of many animals.
Spe' ci es, a word used in classification to designate a group of animals differing only in minor details.