Chapter X.— STRUCTURE AND DEVELOPMENT OF THE REPRODUCTIVE 



ORGANS. 



THE FEMALE REPRODUCTIVE ORGANS. 

 THE OVARY. 



In order to understand the structure of the ovary and the changes it undergoes it 

 is necessary to examine this organ at different stages of development and in the various 

 phases of the sexual life of the animal. The external eggs borne on the swimmerets 

 of the female serve as a gauge to determine the age of the developing ovarian ova. 



I have already given an account of this organ in my paper on Alpheus (94, see 

 also 90 and 93) and have illustrated the growth of the eggs. Bumpus (30) has also 

 devoted considerable attention to this subject and has figured certain structural phases 

 of the ovary, but the early development of this organ has not been touched upon and 

 there are important anatomical facts which have not yet been noticed or illustrated. 

 I shall therefore deal with this subject in detail, though in doing so it will be necessary 

 to repeat some facts which are already known. 



The time of the year when the ovary becomes mature and the size which the 

 spawning female attains are discussed in other parts of this work. 



THE RIPE OVARY. 



The ripe ovary, which I will first describe (plate 36, fig. 123), occupies, as we have 

 seen, the dorsal part of the body cavity. The anterior lobes encircle the stomach, while 

 the hinder ones extend sometimes as far backward as the fifth abdominal somite. 

 The ovarian wall, though often quite thick, is very transparent, and the ripe eggs 

 give it a dark green, beaded appearance. The walls, if mutilated, immediately collapse 

 and the perfectly ripe eggs flow out in a stream. 



The structure of a nearly mature ovary is seen in fig. 141, plate 39. Most conspic- 

 uous are the massive ova filling the lumen of the thick, tubular wall. Immediately 

 next to the latter are seen very characteristic structures which I shall call ovarian 

 glands (0. G.). Immature ova of varying size are interspersed among the glands and 

 dip down between the ripe peripheral eggs. These structures, together with irregular 

 blood sinuses (Bl. 8.) and strands or nodules of muscle and connective tissue, make 

 up the substance of this organ. 



The glands are folds of follicular epithelium similar in origin to that which encap- 

 sules the larger ova. The long axis of the fold is parallel with the ovarian wall. The 

 glandular fold consists of a structureless basement membrane and of columnar 

 epithelial cells (fig. 152, plate 41). The nuclei generally lie at the deeper ends of the 

 cells, the protoplasm of which is decidedly granular, and cell walls are very indis- 

 tinct after the ordinary methods of treatment. Occasionally a glandular fold is seeu 

 (plate 41, fig. 153) which has a very different character from the structure just 

 described. It is expanded into an oval or oblong form, and its epithelial wall appears 

 in a much disordered state. It is highly vesicular, containing numerous vacuoles, 

 which probably represent fat globules (F. G.) ; cell walls are absolutely effaced ; nuclei, 



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