selenizone n. [Gr. selene, moon; zone, girdle] (MOLL: Gastropoda) In dibranchiates, a spiral band of crescentric growth lines or threads (lunulae) on the shell surface due to the semicircular end of a notch or slit on the outer lip; a slit band; corresponds to the anal fasciole of some other groups.
self-cleansing (MOLL: Bivalvia) Removal and ejection of pseudofeces.
self-fertilization The union of gametes derived from the same individual; autogamy; automixis. see cross-fertilization.
selfing see self-fertilization self-sedimentation (MOLL: Bivalvia) In oysters, pseudofeces and feces that are ejected.
sellate a. [L. sella, saddle] Saddle-shaped.
seller groove (ARTHRO: Crustacea) In Decapoda, a short transverse groove on the carapace, dorsally anterior to the cervical groove of Nephropidae.
selva n. [L. silva, wood] A tropical rain forest.
selvage n. [A.S. self; edge, its own proper edge] (ARTHRO: Crustacea) In Ostracoda, the principal ridge of the contact margin sealing the valves closed.
sematic a. [Gr. sema, sign] Functioning as a warning of danger, as signalling colors of insects, or disagreeable odors of certain poisonous or dangerous animals. see allosematic, antiaposematic, aposematic, parasematic, pseu-dosematic, episematic, pseudepisematic, pseu-daposematic.
sematophore see spermatophore semelparity n. [L. semel, once; parere, to bear] Producing young only once in a lifetime. semelparous a.
semiaquatic a. [L. semis, half; aqua, water] Living in wet places, or partially in water.
semidominant see codominant semifenestra a. [L. semis, half; fenestra, window] (NEMATA: Secernentea) In Heterodera one of a pair of openings in the vulval cone separating the vulval bridge. see circum-fenestrate.
semigeographic speciation see parapatric speciation semilunar a. [L. semi, half; luna, moon] A half-moon shaped marking with sharp ends.
seminal a. [L. semen, seed] Pertaining to structures in which sperm are involved.
seminal bursa (PLATY: Turbellaria) A term used to describe the sac for receiving sperm during copulation that will be stored for a period of time; bursa seminalis. see bursa copulatrix.
seminal canal (ARTHRO: Insecta) In female Coleoptera, a duct or canal that connects the spermatheca with the vagina, functioning in sperm transport.
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