Archive image from page 68 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana05todd Year: 1859 OVUM. 55 and serpents, and in the batrachia, this organ is hollow, and the capsules in which the ovules are formed burst in dehiscence into an internal cavity, whence the ovules escape into the abdomen by the rupture or open- ing of the sack of the oviduct, generally at one, but sometimes, as in the frog, at a greater number of places. In the higher animals, in which the ovules escape from the external surface of the ovary, their en- trance into the oviduct is
Archive image from page 68 of The cyclopædia of anatomy and. The cyclopædia of anatomy and physiology cyclopdiaofana05todd Year: 1859 OVUM. 55 and serpents, and in the batrachia, this organ is hollow, and the capsules in which the ovules are formed burst in dehiscence into an internal cavity, whence the ovules escape into the abdomen by the rupture or open- ing of the sack of the oviduct, generally at one, but sometimes, as in the frog, at a greater number of places. In the higher animals, in which the ovules escape from the external surface of the ovary, their en- trance into the oviduct is in general secured by the temporary apposition of the dilated upper end or infundibulum of the oviduct to the ovary, or the capsule containing a ripe ovule; in the other animals, in which the ova come from the interior of the hollow ovary, the apposition of the oviduct does not ap- Fig. 38. Common adder, in which the ova have descended to occupy both oviducts, five in the right, and three in the left: the infundibulum is shown in each ovi- duct; a'a, the right and left ovaries, each forming a sac, opening anteriorly near the infundibulum for the discharge of the ova, which, when ripe, fall into the interior of the sac, and thence pass into the oviduct. pear to be so direct, and there are various other means by which the ova, when they have escaped into the abdominal cavity, reach the open extremity of the oviduct. It is in the class of fishes that the transi- tion occurs from the higher to the lower type of organisation of the ovaries and oviducts. In all of them the ovules are formed in ova- rian follicles, and escape by dehiscence from these follicles; but there are several modifi- cations of the relation between the oviduct and ovary among them. 1st. In the sharks and rays, as already stated, the arrangement is nearly similar to that existing in higher ani- mals. The ova, which are of large size, come to maturity singly, or in small numbers at once: on being discharged
Size: 949px × 2108px
Photo credit: © Actep Burstov / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: 1850, 1859, anatomy, archive, book, bookauthor, bookdecade, bookpublisher, booksponsor, booksubject, bookyear, drawing, historical, history, illustration, image, london_sherwood_gilbert_and_piper, mblwhoi_library, page, physiology, picture, print, reference, todd_robert_bentley_1809_1860, vintage, zimmermann_a_albrecht_b_1860, zoology
