Studies on Gonad Maturity in Some Marine Invertebrates-II

Structure of the Reproductive Organs of the Lined Shore Crab

Abstract

The present paper deals with histological observations of the reproductive organs of the lined shore crab, Pachygrapsus crassipes, (Grapsidae, Brachyura), known as a common crab which widely inhabits the rocky beaches of the Japanese Islands. The materials used were collected from the coast of Niigata City, facing the Japan Sea, and the period of collection extended from April to November, 1969.
The male reproductive organ consists of six parts, and are as follows: the testis, coiled vas deferens, median vas deferens, prostate gland, ejaculatory duct, and external penis. The thicker part of the epithelium of the coiled vas deferens produces the secretory droplets, which are weakly positive to PAS reaction, and are released into the lumen. The prostate gland, consisting of many blind tubes with a simple layer of epithelium, produces secretory droplets of the spindle shape that become stained with basophilic dyes. Both types of secretory droplets reach the ejaculatory duct, and move to the basal portion of the penis together with spermatozoa. While the outer surface of the penis is coated with a chitinous layer, its epithelium constituting an inner duct is invaginated deeply into the cavity.
The female reproductive organ consists of the ovary, chitinated short duct, and the seminal receptacle. In the central part of the ovary a germinal center is visible, and the oocytes develop and migrate toward the cortical region of the ovary. A simple layer of the columnar epithelium of the seminal receptacle produces the basophilic substance in colloidal form which are discharged into the lumen. The secretory function of this epithelium is more active in the virgin crab than in crabs after copulation.
There could not be seen spermatophore and/or its related material anywhere in the gonoducts of this crab.