testis

Male reproductive organ, producing sperm. (Pl. testes) [Butler, T.H.].

The organ which produces the male gametes or spermatozoa [Ingle, 1983].

(Order Cladocera):

Paired section of male reproductive system in which sperm are produced. Testes extend through anterior part of trunk, one to each side of midgut; opens to exterior via ventrally directed vas deferens [Stachowitsch, 1992].

(Order Notostraca):

Gonad [Stachowitsch, 1992].

(Order Diplostraca):

Gonad [Stachowitsch, 1992].

(Order Anostraca):

Paired section of male reproductive system in which sperm are produced; extends from third or fourth abdominal somite anteriorly to first and second abdominal somites (= genital somites). Each testis opens to exterior via vas deferens and penis [Stachowitsch, 1992].

(Class Cephalocarida):

One of two sausage-shaped sections of male reproductive system in which sperm are produced. Located dorsal to digestive tract and extends from 12^th to 7^th postcephalic segments; anterior ends joined. Each testis opens to exterior on sixth thoracomere via vas deferens and gonoduct (common male and female duct) [Stachowitsch, 1992].

(Order Cumacea):

Section of male reproductive system in which sperm are produced. Paired, tube-like, located on each side of pereon. Each testis opens to exterior on last (fifth) pereon segment via vas deferens [Stachowitsch, 1992].

(Order Tanaidacea):

Paired, relatively short section of male reproductive system in which sperm are produced. Both testes open into common seminal vesicle [Stachowitsch, 1992].

(Order Decapoda):

Typically paired, expanded section of male reproductive system in posterodorsal region of cephalothorax. Connected by bridge, each testis opening to exterior on basal segment (coxa) of last pereopod via vas deferens. (paired, fused; multilobed, tubular) [Stachowitsch, 1992].

(Order Amphipoda):

Paired section of d reproductive system in which sperm are produced. Elongate, cylindrical, extending between heart and digestive tract from third to sixth pereon segments (pereonites); each testis opens to exterior on last (seventh) pereonite via vas deferens and penis [Stachowitsch, 1992].

(Order Isopoda):

Paired section of d reproductive system in which sperm are produced. Located dorsolateral to digestive tract in pereon, each testis opening to exterior on last (seventh) pereon segment via vas deferens [Stachowitsch, 1992].

(Order Mysida):

Paired section of male reproductive system in which sperm are produced. Located in thorax and differentiated into series of spermatic sacs. Opens to exterior via seminal vesicles, vasa deferentia, ejaculatory ducts, and penes [Stachowitsch, 1992].

(Order Stomatopoda):

Section of male reproductive system in which sperm are produced. Elongate, paired, extending from third abdominal somite (pleomere) to telson between heart and digestive glands. Fused posteriorly in telson and opening to exterior on eighth thoracic somite (thoracomere) via vasa deferentia and penes [Stachowitsch, 1992].

(Order Leptostraca):

In male reproductive system, pair of slender, tubular organs in which sperm are produced. Located between digestive tract and heart and extending through most of body; each tesis opens on coxa of eighth thoracopod via vas deferens [Stachowitsch, 1992].

(Subclass Branchiura):

Paired, expanded section of male reproductive system in abdomen. Each testis is connected to unpaired seminal vesicle in thorax by vas efferens. (elongate elliptical, elongate ovate, lunate) [Stachowitsch, 1992].

(Subclass Cirripedia):

Large, paired section of male reproductive system in which sperm are produced. Located in anterior region of body and opening to exterior via pair of vasa deferentia and unpaired penis [Stachowitsch, 1992].

(Subclass Mystacocarida):

Unpaired section of male reproductive system in which sperm are produced; extends throughout posterior region of thoracoabdomen. Bears several pairs of dorsal diverticula and opens to exterior through anteriorly directed vas deferens [Stachowitsch, 1992].

(Class Ostracoda):

In free-living copepod typically unpaired, in parasitic copepod typically paired, expanded section of male reproductive system in which sperm are produced. Located dorsally, above midgut, near border of head and thorax. Opens to exterior on first abdominal segment (genital somite) via regionated vas deferens. (paired, unpaired) [Stachowitsch, 1992].

(Class Ostracoda):

Section of male reproductive system in which sperm are produced. Located in posterior region of trunk or between body and valve and opening to exterior via vasa deferentia. (paired, unpaired; coiled, elongate, four-lobed = quadripartite, lobed, simple, spheroid, tube-shaped) [Stachowitsch, 1992].

(Class Remipedia):

Paired section of male reproductive system in which sperm are produced; located ventral and dorsal to midgut in posteriormost seventh to about tenth trunk segment [Stachowitsch, 1992].

(Superorder Syncarida):

In anaspidacean, section of male reproductive system in which sperm are produced. Paired, extending from fifth thoracic somite to posterior end of abdomen. Each testis opens to exterior via vas deferens. Restricted to abdomen in bathynellacean [Stachowitsch, 1992].

(Order Thermosbaenacea):

Section of male reproductive system in which sperm are produced. Paired, relatively short, located anteriorly in posterior cephalon/first thoracomere region. Each testis opens to exterior on last (eighth) thoracomere via elongate vas deferens [Stachowitsch, 1992].

(Order Euphausiacea):

Section of male reproductive system in which sperm are produced; located between heart and digestive tract in thorax. Each testis (or each side of unpaired testis) opens to exterior on last (eighth) thoracomere via vas deferens. (single, paired) [Stachowitsch, 1992].