COMPARISON OF OVARIIiS 



inclusions as the cells begin the degeneration process which is first charac- 

 terized by a breaking down of the yolk. 



Monthly Changes in the Ovaries 



The foregoing account has dealt with the structure of the mature ovary 

 as it may be seen in both B. cognatus and B. w. tvoodhousii. The ovarian 

 changes which occur month by month during the breeding periods of the 

 two species were studied in order to see whether there is any correlation 

 between them and to see if this evidence corroborates our ideas concerning 

 the breeding habits of these species. The observations to follow present a con- 

 densed review of the average microscopic and macroscopic conditions found 

 in ovaries representative of each month. It is not the purpose of this study 

 to account for all the numerous variations from this general monthly plan; 

 however, striking deviations will be noted. 



Bujo cognatus Say 



March — Macroscopically, the ovary is highly pigmented, several with 

 some lobes collapsed; eggs often present in coelom or oviduct (especially if cap- 

 tured during breeding activities). Microscopically seen, large yolky oocytes 

 press against the ovarian wall with many others approaching the end of the 

 primary growth period. Disregarding the numerous primordial germ cells, 

 the predominating oocyte diameters are 0.7 and 0.9 mm. (range to 1.06). 



April — Macroscopic signs of ovulation less general; ovaries darkly pig- 

 mented and heavily lobed; predominating oocyte sizes as in March ( but range 

 only to 0.94 mm.). Collection data show that fewer of the animals were 

 actually breeding as captured which probably accounts for some of the 

 difference. 



May — Much like April, with two notable exceptions: ( 1 ) oocyte diameter 

 generally 0.7-0.8 mm. with no significant range above this, and (2) ten 

 ovaries appearing mature macroscopically with a preponderance of oocytes 

 of about 0.4 mm., and ovary wall not collapsed. Since there could be no 

 doubt that these were mature toads, it probably indicates that individuals 

 differ in the seasonal relations of the ovarian cycle. 



]une — Little change from preceding month. Oocyte diameter generally 

 between 0.3 and 0.5 mm. in collapsed lobes (ranging to 0.62 mm. in nine 

 studied microscopically). In full lobes, 0.9 to 1.0 mm., the rule, the largest 

 being 1.02. 



July — In all specimens, an unusual number of collapsed lobes with eggs 

 in coelom and oviducts; full lobes dark and fully prepared to release oocytes. 

 Predominating diameters 0.8 to 0.95 ranging to 1.12 mm. Most of these 

 specimens were secured from a single breeding congress which accounts for 

 the small range given in Table I. If even half of the animals had ovulated, 

 this would explain the sudden drop in percentages shown. 



August — General preparedness for ovulation evident in six available 



