Terminal gravid proglottid
Terminal gravid proglottids
Squalus acanthias Linnaeus, 1758
Black Sea, Aleksandrovskaya Bay, Sevastopol
Black Sea, Evpatoriya; Black Sea, Karantinnaya Bay, Sevastopol
This species is strongly expressed in hyperapolysis. The immature specimens are 4.0 to 13.0 in length and 0.085 to 0.1 mm wide; strobila contains 150 - 431 young immature proglottids, 50 x 100. Scolex large, 540 - 600 x 670 - 700; with 4 oval botridia, 500 - 600 x 150 - 350; each of them contains three contiguous locules, one anterior and two posterior ones. The ratio of the width of the anterior locules to the width of the connected posterior locules is 1: 1.8-2; anterior locules 287 - 350 x 133 - 167, posterior - 300 - 350 x 233 - 300. Cephalic peduncle 500 - 600 x 100 - 200.
The development of the reproductive system and the maturation of eggs occurs in separate proglottids, which freely exist in the intestine of the shark. Mature proglottids 4,16 - 6,2 х 1,02 - 2,01 mm, with pointed anterior end not covered with microtriches. In mature proglottids, 86 to 106 testes, with a diameter of 65 to 72; They are located in two layers and extend from the front edge of the proglottide to the level of the genital atrium. Cirrus sac large, oval, 360 x 600, contains armed cirrus, the seminal duct forms several median loops. Posterior pores lateral, open at a distance of 65-70% from the posterior edge of proglottid. The vagina, without bending, extends from the ootype to the median line of the proglottid and, at the level of the anterior margin of the cirrus sac, turns to the genital atrium, opening into the common genital atrium in front of the cirrus sac; the vaginal sphincter is absent. The genital atrium is 240-260 x 120-150. The ovary is located at the posterior edge of the proglottid, median, H-shaped, four-bladed in cross section; wings are symmetrical in length, 1.56 - 1.8 x 0.75 - 0.84 mm. Vitellaria follicular, with a diameter of 40 to 50, consist of 2 lateral bands, a width of 360-480; extend from the anterior to posterior edge of proglottid; thinning at the level of the genital atrium and interrupted in mature proglottids during the transition from one proglottidium to another. Eggs are oval, 50 - 70 x 40 - 50