Figure 9.

Restricted lobular testis of the poeciliid Poecilia latipinna. (A). Transverse sections of both testes. Similar to that described in goodeid testis, spermatogenesis occurs at the periphery (P) or distal part of the testis lobules. Sperm are released, into a net of efferent ducts (Ed). (B,C). The germ cells in spermatogenesis are within cysts, the later stages (large arrow) are progressively closer to the efferent ducts (Ed). The spermatozoa are located in groups of spermatozeugmata (SP). A characteristic of the spermatozeugmata in poeciliids is that the heads of the spermatozoa are oriented toward the Sertoli cells. In the efferent ducts, the spermatozeugmata are surrounded by a PAS+ mucoprotein complex (mp). (D,E). Lobules at the testicular periphery with cysts of germ cells during several stages of spermatogenesis, as spermatogonia (Sg), restricted at the periphery, primary spermatocytes (1Sc), early spermatids (eSt), late spermatids (lSt), and spermatozoa (Sz) in spermatozeugmata. (F). In the efferent ducts (Ed), the spermatozeugmata (SP) are surrounded by the PAS+ mucoprotein complex (mp). The nuclei of the spermatozoa are oriented toward the Sertoli cells. A,B: PAS; C-F: Hematoxylin-eosin. A: Bar = 200 μm. B,C: Bar = 50 μm. D: Bar = 20 μm. E,F: Bar = 10 μm.