. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. 64 THE VERTEBRATE OVARY AND ITS RELATIONSHIP TO REPRODUCTION OVIDUCT L LO PI AN TUBE). AT E R AL AL CANAL VA6INAL E -SAC URINARY BLADDER UR 0 G EN I TAL SINUS Fig. 35. Reproductive structures of female opossum shown from the ventral view. Ob- serve that the ovary and infundibular portion of the Fallopian tube lie dorsal to the horn of the uterus. functions to secrete an albuminous coating which is applied to the egg during its passage through this
. Comparative embryology of the vertebrates; with 2057 drawings and photos. grouped as 380 illus. Vertebrates -- Embryology; Comparative embryology. 64 THE VERTEBRATE OVARY AND ITS RELATIONSHIP TO REPRODUCTION OVIDUCT L LO PI AN TUBE). AT E R AL AL CANAL VA6INAL E -SAC URINARY BLADDER UR 0 G EN I TAL SINUS Fig. 35. Reproductive structures of female opossum shown from the ventral view. Ob- serve that the ovary and infundibular portion of the Fallopian tube lie dorsal to the horn of the uterus. functions to secrete an albuminous coating which is applied to the egg during its passage through this region. In amphibians, reptiles, and birds it forms the major portion of the oviduct, but in mammals it is much reduced in size and extent. In the latter group it is referred to as the uterine or Fallopian tube. The uterus is a muscular, posterior segment of the oviduct. Like the anterior glandular portion of the oviduct, it also has glandular functions, but these are subservient to its more particular property of expanding into an enlarged compartment where the egg or developing embryo may be retained. The protection and care of the egg or of the embryo during a part or all of its development, is the main function of the uterus in most vertebrates. In the frogs and toads, however, this structure seems to be concerned with a "ripen- ing" process of the egg. Large numbers of eggs are stored in the uterine sac of the frog for a period of time before spawning. Various degrees of union between the uterine segments of the two ovi- ducts are found in mammals. In the primates they fuse to form a single uterine compartment with two anterior uterine tubes (fig. 29). In carnivores, there is a caudal body of the uterus with two horns extending forward to unite with the uterine tubes (fig. 36). In the rat and mouse, the uterine seg- ments may be entirely separate, coming together and joining the single vaginal chamber (fig. 37). In the opossum the uterine segments are entirely s
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