Fasciola hepatica is hermaphrodite but usually cross fertilisation takes place. The reproductive organs are well developed and complex.
Male Reproductive System of Fasciola Hepatica
The male reproductive system consists of testes, vasa deferentia, seminal vesicle, ejaculatory duct, cirrus or penis, prostate glands and genital atrium.
Testes
These are two in number, much ramified tubular and placed one behind the other (i.e., with tandem arrangement) in the posterior middle part of the body. In fact, they occupy major space from behind the middle part of the body of Fasciola. The cells lining the wall of testes give rise to spermatozoa.
Vasa Deferentia
A narrow and slender vas deferens or sperm duct arises from each testis and runs forwards.
Seminal Vesicle
The two vasa deferentia unite together near the acetabulum (ventral sucker) and become dilated to form a muscular, elongated, broad, baglike seminal vesicle or vesicula seminalis. It serves the purpose of storing sperms.
Ejaculatory Duct
The seminal vesicle continues anteriorly into a very narrow and coiled duct called ejaculatory duct.
Cirrus
The cirrus (penis) is a muscular and elongated structure into which ejaculatory duct opens. The cirrus opens by male genital aperture in a common genital atrium. The cirrus of F. indica is covered with small spines.
Prostate Glands
The ejaculatory duct is surrounded by numerous unicellular prostate glands. These glands open into the ejaculatory duct and their secretion (alkaline) helps in free movement of sperms during copulation.
Genital Atrium
The genital atrium is a common chamber for male and female genital apertures, it opens externally by a gonopore lying ventrally in front of the acetabulum. The cirrus can be everted through the gonopore during copulation. The cirrus or penis, seminal vesicle and prostatic glands are surrounded in a common
Female Reproductive System of Fasciola Hepatica
The female reproductive system consists of ovary, oviduct, uterus, vitelline glands, Mehlis’s glands and Laurer’s canal.
Ovary
The ovary is single, tubular, highly branched and situated to the anterior of testes at the right side in anterior one-third of the body.
Oviduct
All the branches of ovary open into a short and narrow tube called oviduct. The oviduct travels down obliquely and opens into the median vitelline duct.
Uterus
From the junction of oviduct and median vitelline duct arises a wide convoluted uterus having fertilised shelled eggs or capsules. The uterus opens by female genital aperture into the common genital atrium on the left side of male genital aperture.
The uterus is comparatively small and it lies in front of the gonads. The terminal part of uterus has muscular walls, referred to as metraterm which ejects the eggs and also sometimes receives the cirrus during copulation.
Vitelline Glands
On both lateral sides and also behind the testes are numerous follicles constituting the vilellaria, yolk glands or vitelline glands which produce albuminous yolk and shell material for the eggs. The vitelline glands open by means of minute ducts into a longitudinal vitelline duct on each side.
The two longitudinal ducts are connected together by a transverse vitelline duct placed above the middle of the body. The transverse vitelline duct is swollen in the centre to form the yolk reservoir or vitelline reservoir. From the yolk reservoir a median vitelline duct starts and runs forward to join the oviduct.
Mehlis’s Glands
A mass of numerous unicellular Mehlis’s glands is found situated around the junction of median vitelline duct, oviduct and uterus. The secretion of Mehlis’s glands lubricates the passage of eggs in the uterus and probably hardens the egg shells, it probably also activates spermatozoa.
The junction of oviduct and median vitelline duct is swollen to form ootype in certain flukes like F. indica, in which the parts of an egg are assembled and the eggs are shaped, but an ootype is lacking in F. hepatica (according to some authorities).
Laurer’s Canal
From the oviduct arises a narrow Laurer’s canal, it runs vertically upwards. This canal opens on the dorsal side temporarily during breeding season and acts as vestigial vagina to serve as copulation canal.