Accessory prostatic vesicle:   Blind sacs that are separated off of the prostatic vesicle.

 Adhesive folds of female antrum:   Muscular concentric folds of a wide female antrum that surround the female gonopore.

Anterior gland pouch of cirrus sac:  A blind sac that opens into the cirrus sac.

Brain or Cerebral organ:  A mass of nerve fibers surrounded ganglia and enclosed by a membranous capsule.

Bulbous antrum or vagina bulbosa:  The wall of the female antrum is  muscularly thickened.

 Bursa copulatrix:  A blind muscular sac that extends anteriorly from the vagina.

 Cement ducts:  The portion of the vagina that receives the cement gland secretions. In some species evaginations in the lining of the vagina which receive the                                         secretions of the cement glands are termed cement ducts.

Cement glands:  Glands that secrete a gelatinous substance which aid in the fixing the eggs to the substrate.

Cement pouch:  An inflated part of the vagina which receives the secretions of the cement glands.

Cerebral eyes:  Eyes located over the brain and may extend a short distance anteriorly.

 Cirrus:  A male copulatory apparatus that is everted to the exterior by turning inside out.

Cirrus sac:  A hollow muscular structure that is lined with spines and teeth. 

Common antrum:  A chamber that combines both the male and female antrums.

Common gonopore:  The opening of the common antrum to the exterior.

 Duct of Lang’s vesicle:  The duct that continues from the vagina to Lang’s vesicle.

 Ejaculatory duct:  The male duct from the proximal end of the seminal vesicle to the tip of the penis or cirrus.

False seminal vesicle:  The sperm ducts expand posteriorly into thin walled chambers that collect the sperm then narrow into sperm ducts prior to their union  as a common sperm duct.

Female antrum:  The chamber of the female reproductive system which exits to the exterior.

Female gonopore:  The opening of the female reproductive system to the exterior.

Frontal eyes:  Eyes spread over the region between the brain and the anterior margin.

 Genital pit:  A pit located between the male and female gonopores.

 Genito-intestinal connection:  A duct connecting the female reproductive system with the intestine.

Granule mass of the brain:  A group of sensory cells located outside the brain.

 Intestinal network:  Intestinal branches subdivide repeatedly towards the periphery  of the body and the subdivisions anastomose forming a network.

Lang’s vesicle:  A blind sac that is the continuation of the vagina after the entrance of the oviduct.

 Main intestine:  The central tube that runs most of the length of the body above the  ruffled pharynx or behind the tubular pharynx.

 Male antrum:  The chamber that contains the penis papilla.  The chamber may be  short and narrow or wide and spacious.

Male gonopore:  The opening to the exterior of the male reproductive system.  In the genus Stylostomum the male gonopore may be united with the mouth to form a common antrum.

Marginal eyes:   Eyes that occur along the body margin.  The eyes may encircle the  margin or an anterior portion of the margin.

Marginal groove:  A subventral groove on the anterior margin of the body whose function is unknown but probably chemosensory.

Mouth:  The opening to the exterior from the pharyngeal cavity.  The Pharynx is extended through the mouth.

Nuchal tentacles:  Tentacles in the region of the brain.  They may be muscular and retractile and usually free of pigment.

Penis papilla:  Is a muscular projection that is extended to the exterior.  It may be a very low elevation, or a conical projection.

Penis pocket:  In some species the male antrum is divided into wide outer chamber and a narrower inner chamber the penis pocket.  The penis pocket encloses the                             penis papilla.

Penis sheath:  The male antrum may have a circular eminence, that simulates a small penis papilla.  The penis sheath appears to act as guide for the penis papilla or penis stylet.

Penis stylet:  A hard hollow tube that is attached to the penis papilla.  The penis papilla is usually greatly reduced when a stylet is present.  The stylet may be long                             or short, straight, curved or coiled. 

Pharyngeal cavity:  The longitudinal chamber in which the pharynx is contained.

Pharynx:  The pharynx is a body fold that projects into the pharyngeal cavity and is extended externally through the mouth.  The pharynx maybe ruffled or tubular.

 Prostatic diverticula:  A sac shaped projectionfrom the prostatic vesicle.

 Prostatic duct:  The duct of a free prostatic vesicle that connects to the ejaculatory duct.

Prostatic vesicle:  A cylindrical, spherical or oval structure with a muscular wall and  glandular epithelial lining.  When the lining is elevated into chambers the                                   prostatic vesicle is said to be chambered.  The gland cells maybe in the epithelial lining, muscular lining or outside the vesicle.  When the lumen of the  prostatic vesicle forms part of the ejaculatory duct the prostatic vesicle is termed  interpolated.  When the prostatic vesicle is separated from the ejaculatory duct it  is termed free.

Pseudotentacles:  These are folds of the anterior margin. The pseudotentacles of  Pseudoceros are simple folds while those of Pseudobiceros are ear-like and pointed or square with lateral ruffles.

Seminal vesicle:  The muscular expansion of the sperm duct which may hold sperm  prior to its being expelled.  When spermiducal bulbs are present the structure                                     appears as a tripartite seminal vesicle. 

Sperm duct:  The ducts that collect sperm from the testes and lead to the male copulatory apparatus.  In some instances the ducts may join to form a common                                     sperm duct.

Spermiducal bulb:  The distal part of the sperm ducts which is muscular prior to their combining into a common duct, which may be the seminal vesicle or the                             ejaculatory duct.

Spermiducal vesicle:  The expansion of the sperm ducts into thin walled ducts.

Sucker:  A glandular-muscular organ adhesive organ which forms either an  elevation or a depression on the ventral surface.

Tentacular eyes:  Eyes that are located in or around the tentacles.  If tentacles are  absent  the eyes at the site where the tentacles would have been.

Testes:  Small structures in the lateral body regions that produce sperm.

Uterine network:  Uterine vesicles unite to form a network

 Uterine vesicle:  One or more sac like appendages of the uterus for storage of egg  capsules.

Uterus:  When an oviduct is distended because of stored eggs it is termed a uterus.                            

Vagina:  That portion of the female duct distal to the entrance of the paired or common oviduct that leads to the female gonopore.

Vagina bulbosa:  The muscular or bulbous portion of the proximal vagina.

 Vaginal duct:  A duct that continues proximally from the entrance of the oviducts  into the vagina and continues either to the ventral surface where it terminates at a                           vagina pore separate from the female gonopore.  The duct may curve to enter the  vagina or open into the intestine.