prostomium

[Gr. pros tom i on =a mouth, spec if. of a river: pref. pro-, and Gr.stoma =mouth.] Zool.: A portion of an animal before the mouth. Used of the Plan arid a and certain Annelids. pros-trate, adj. [Lat. pro stratus, pa. par. of Anat.: The largest of all the organs connected prosterno to throw forward on the ground: pro = with the male generative system. It is an aggregation of glands of the racemose type, resembling a chestnut in size and shape, situated before the neck of the bladder, behind the symphysis pubis , and surrounding the first portion of the urethra. Its secretion (a white viscid humor, discharged into the urethra by ten or twelve excretory outlets) is probably allied to that of the vesiculæ semina les , for which it serves as a vehicle.