328 GLOSSARY 
REVERSION.—The reappearance in the offspring of a 
character proper to a more or less remote ancestor, and not 
exhibited by the immediate parents. 
Rotirers.—A kind of minute aquatic animals. 
SEGMENT.—One of a series of more or less similar trans- 
verse divisions. 
SESSILE.—Fixed and stationary, but (in the strict sense) 
without a stalk. 
SomaTic.—Belonging to the body of a zygote. 
Species, LInNzan.—A group of organisms of closely 
similar appearance. 
SPECIES, JORDAN’S.—A group of organisms believed to have 
arisen by a mutation. (Jordan himself did not, however, 
suppose so.) 
Sport.—A marked mutation—often one occurring under 
domestication. 
StTamMENs.—The organs of a flower which bear the pollen. 
STANDARD.—The large, upright petal at the back of such 
a flower as that of the sweet-pea. 
StigmAa.—The uppermost part of the pistil, upon which the 
pollen is received. 
STRATUM.—A layer. 
STYLE.—A stalk connecting the stigma with the ovary— 
part of the pistil. 
Txsta.—The skin or coat covering a seed. 
THRUM-EYED.—Having the anthers situated at the throat 
of the corolla, and the stigma lower down, enclosed in the 
tube. 
Tusz.—The basal tubular portion of a corolla in which 
the separate petals are closely fused together, as is the case 
with that of the primrose, 
UNICELLULAR.—Consisting of a single cell. 
VaRIATION, CONTINUOUS.—See Chapter IV. 
VARIATION, DisconTINUOUS.—See Chapter V. 
Wincs.—The lateral petals of a pea-flower. 
ZooLocy.—The scientific study of animals, 
ZyGotEe.—The organism produced by the fusion of a pair of 
gametes, 
