. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 210 ANNALS OF THE SOUTH AFRICAN MUSEUM cavity, for, when, they are displaced and fully spread out, they are almost similar in length and width. After extrusion of the eggs, the spent ovaries (fig. 79) are considerably reduced in size, collapsed, and greyish-white in colour. anterior horn of right ovary. Fig. 79. Diagram of spent ovaries of ovigerous female, removed from body and %vdth the oviducts somewhat laterally extended. Each oviduct is a relatively short, broad, thin-walled, transparent tube wh
. Annals of the South African Museum = Annale van die Suid-Afrikaanse Museum. Natural history. 210 ANNALS OF THE SOUTH AFRICAN MUSEUM cavity, for, when, they are displaced and fully spread out, they are almost similar in length and width. After extrusion of the eggs, the spent ovaries (fig. 79) are considerably reduced in size, collapsed, and greyish-white in colour. anterior horn of right ovary. Fig. 79. Diagram of spent ovaries of ovigerous female, removed from body and %vdth the oviducts somewhat laterally extended. Each oviduct is a relatively short, broad, thin-walled, transparent tube which passes outward about midway along the posterior horn of the ovary opposite the third pereiopod. It runs horizontally across the posterior lobe of the digestive gland and curves downward over the lateral margin of the anterior thoracic muscle. In most specimens it enters the base of the third pereiopod anteriorly and describes a course comparable with that of the vas deferens in the fifth walking leg of the male. Travelling between the promo tor and levator limb muscles, it opens on the ventral base of the coxopodite of the third pereiopod (fig. 80). 3. SPECULATIONS CONCERNING FERTILIZATION OF THE EGGS From previous remarks on the external evidences of sexual dimorphism, it is obvious that the male has no intromittent organs. For this and other reasons the process of fertilization of the eggs is problematic. In most Macrura sperma- tophores of some sort or another are deposited on the ventral surface of the female usually in proximit}^ to the genital apertures, and insemination is assumed to take place as the eggs pass over the spermatophores to their attach- ment on the setae of the pleopods. The spermatozoa apparently remain viable within the spermatophores for periods that vary according to the species. Lloyd & Yonge (1947) have reported that in Crangon crangon (vulgaris) the eggs are laid within two days of mating, while, according to Hughes & Matthiessen. Please
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectnaturalhistory, booky
