454 WINTERTON C. CURTIS, 



are found having no apparent connection with the ovary or oviduct 

 (PI, 31, Fig. 1 ov"), but showing ova in various stages of development 

 (PI. 32, Fig. 9 ov"). While the mass of the ovary is solid with no 

 such cavity as that in the testis, the lumen of the oviduct curves 

 around as it enters and is often continued a short distance posteriorly 

 as a central cavity which may divide into two or three short branches 

 extending in the direction of largest lobes (PI. 31, Fig. 4 T). Within 

 are ova in various stages and filling the spaces between them a mass 

 of protoplasm in which are embedded smaller nuclei (PI. 31, Fig. 4, 

 and PI. 32, Fig 9 n). Whether these represent undeveloped germ- 

 cells as Ijima ('84, p. 412) believed, or a connective tissue net-work 

 as Wood WORTH ('91, p. 34) speaks of them, I am unable to say. 

 They certainly serve the latter purpose in the stages of the ovary 

 examined. The fact that the youngest ova are found as nuclei having 

 no cell outline, but embedded in the mass of protoplasm, after the 

 manner which Chichkoff ('92, p. 526) describes for the whole ovary 

 at an early stage "sous forme de simples cellules disposées au sein 

 d'un protoplasma", makes it hard to separate the small dense nuclei 

 with a definite nucleolus and no cell wall (PI. 32, Fig. 9 a), which 

 are certainly ova, from others having their protoplasm in scattered 

 granules of exactly the same appearance but no nucleoli (n). 



Starting with the first stage a in which it is possible to identify 

 the young ova, the next step, judging from the relative size, is the 

 appearance of the cell wall and a gradual increase in all the dimensions 

 until the conditions shown as b in the figures of the ovary obtains. 

 At about this point there seems to be considerable nuclear activity 

 for the cells show their chromatin in irregular strings (h) and finally 

 in long threads tangled through the center of the cell (h'). I have 

 not worked out the relation of the chromatin and base my statement 

 that the activity occurs at this point solely upon the fact that it was 

 noted in cells midway between the smaller stages and the larger ova 

 (d). From the long threads the chromatin seems to go back to an 

 irregular scattered condition and following this comes a clearing up of 

 the nucleus, until the condition shown as d in all the figures obtains, 

 while the cell increases in size. The nucleus has now reached the 

 typical condition in a developing ovum, with a nucleolus and its 

 chromatin in scattered granules of varying size. 



A striking feature in ova of all stages after the appearance of 

 the cell-wall is an increasing number of what seem to be vacuoles 

 containing irregular masses, which may be in turn vacuolated, or 



