. Journal of anatomy. a rule, an anteriorportion, and it usually surrounds the urethra with a ring of glandulartissue; in Type II. the prostate, though well developed, is confined to theback of the urethra. The descensus of the testes is periodic in all forms,and during the breeding season the descended organs reach to remarkabledimensions when compared to the body size of some of the very dimmutivespecies. The condition in Vesperugo temminckii is illustrated from specimensshot on the wing during the breeding season in Nubia (see fig. 5). Thesite of the scrotal area varies. In many species of
. Journal of anatomy. a rule, an anteriorportion, and it usually surrounds the urethra with a ring of glandulartissue; in Type II. the prostate, though well developed, is confined to theback of the urethra. The descensus of the testes is periodic in all forms,and during the breeding season the descended organs reach to remarkabledimensions when compared to the body size of some of the very dimmutivespecies. The condition in Vesperugo temminckii is illustrated from specimensshot on the wing during the breeding season in Nubia (see fig. 5). Thesite of the scrotal area varies. In many species of Type I. the scrotum is 54 Professoi Frederic Wood Jones post-anal, and this condition is figured as it occurs in Vcsperugo serotinus(see fig. 6). A post-anal scrotum does not occur in any members of thePhyllostomids of which I have accounts or specimens. Embryonic Stages. The developmental stages, in such embryos as I have been able to obtain,leave no doubt that the evolution of the genitalia follows the lines of the. Fin. 7. — Plecotus auritus. External genitalia of a male embryoof 9 mm. reconstructed from serial sections. cloaca explicata, and is effected by outfolding of the cloaca upon the surfaceof the body, the circum-anal or retro-anal pouch being a remnant of thecloacal margin. The phase seen in a 9-mm. male embryo of Plecotusauritus may serve to illustrate this point (see fig. 7). In the male The Genitalia of the Cheiroptera 55
Size: 1384px × 1805px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1860, booksubjectanatomy, bookyear1867
