Fig. 9

The detailed anatomy of the sperm storage organ (spermatheca) in inseminated female Nephrops norvegicus (b–h: Light micrographs of histological sections stained with trichromatic Masson–Goldner). Several spermatophores are observed in different areas of the spermatheca. a Macrograph of the ventral side of the female sternum showing the spermathecal orifice formed by an anterior central suture (as) and two posterior sutures (ps) between sternites 7 and 8. The gonopores (go) are located on the coxae of the third pereiopods (P3). Orientation of histological transverse sections through the spermatheca in B-D are indicated by dotted lines in the inset image. a, b Section through the large anterior storage area of the spermatheca on the level of the anterior central suture (as). c In the middle part, the spermatheca is constricted by sternite 8. d The spermatheca forms two separate processes most posteriorly filled with spermatophores. e, f Details of spermatophores located in the posterior processes of the spermatheca. g, h Spermatheca in a female prior to ecdysis. The old cuticle consisting of endocuticle and exocuticle and a thin red-staining epicuticle is delaminated from the newly formed exocuticle. Spermatophores are disintegrated and a spermatophore wall is no longer developed. 7 = sternite 7, 8 = sternite 8, as = anterior central suture, eg = eggs, en = endocuticle, ex = exocuticle, go = gonopore, mu = musculature, nc = new cuticle, oc = old cuticle, P = pereiopods, ps = posterior suture, se = seminal fluid, sp = spermatophore, st = spermatheca, sw = spermatophore wall