BENIRSCHKE ET AL.: OVULATION IN DOLPHINS 



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Figure 24. — Endometrium of uterus in Figure 

 23. The marked stromal edema ( E) and distended 

 glands (G) of basal endometrium are tj^pical of 

 late pregnancy. The superficial endometrium is 

 infiltrated by polymorphonuclear leukocytes that 

 exude into the glandular limiina (arrow). No sur- 

 face stromal hyalinization has yet taken place. 

 The former interdigitation of placental villi with 

 surface endometrium can be imagined from the 

 irregularities the surface presents (hematoxylin 

 andeosin x 100). 



luteum, presumably destined to involute shortly. 



GROUP Vic— This composes 15 animals (8 S. 

 longirostris; 7 S. a^^enuato) measuring 162-193 cm 

 whose features are listed in Table 9. These non- 

 pregnant dolphins possessed histologically re- 

 gressing corpora lutea. Eight animals in fact had 

 corpora albicantia and were probably misclas- 

 sified by the gross observations because the corpus 

 luteum in each case was recently involuted, had 

 still some vascularization and microscopic in- 

 flammation. Similarly, the endometria in these 

 specimens usually had inflammation and hyalini- 



zation and were most likely recently delivered. 

 This is further supported by the disparity in 

 uterine horns. These animals were not listed as 

 lactating either because this feature had been 

 overlooked or perhaps the calves had died or were 

 aborted. This material does not allow this dif- 

 ferentiation. 



Six of the remaining seven animals had corpora 

 lutea with histologic signs of early degeneration. 

 Two had late secretory endometrium and this 

 would likely to have involuted upon further re- 

 gression of the corpus luteum since pregnancy did 

 not occur. Two animals had marked chronic en- 



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