BENTRSCHKE ET AL.: OVULATION IN DOLPHINS 



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Figure ll. — Portion of active corpus luteum of earliest pregnancy with cavity at bottom right and ovarian stroma (S) at top left (no. 3, 



Table 4; hematoxylin and eosin x 100). 



come edematous (Figure 12). At this stage the 

 glands are empty and crowded in the basal por- 

 tions. Their epithelium lacked mitoses. With ad- 

 vancing pregnancy the edema diminished while 

 secretion accumulated in glands. Most charac- 

 teristic, however, is the development of a rich 

 capillary network with congestion, most notably 

 in the superficial strata (Figure 13). Despite the 

 presence of significant chronic endometritis in two 

 cases, normally developing early embryos were 

 found. 



Group IV, Late Pregnancy 



We selected four S. longirostris and two S. at- 

 tenuata between 165 and 199 cm in length and 



embryos of 300-725 mm in length (the S. attenuata 

 fetuses were lost at sea) for this comparison (Table 

 5). All implantations were in the larger left horn 

 but a portion of the membranes traversed into the 

 right horn. The large single corpus luteum of these 

 six specimens was present in the left ovary. 



The superficial endometrium was extremely ar- 

 borized with distended glands into which the villi 

 of the epitheliochorial placenta penetrated, form- 

 ing an intimately interdigitating connection (Fig- 

 ure 14). The basal endometrium was edematous 

 and glands contained secretion. With advancing 

 gestation the villous arborization increased. The 

 corpus luteum had characteristic appearance 

 (Figure 15). Among the plump, eosinophilic luteal 

 cells streamers of fibrocytes gave the first appear- 



Table 5. — Group IV: Late pregnant controls. Specimen no. 1-4 Stenella longirostris, captured October 1978; no. 5-6 S. attenuata, 



captured July 1976. 



515 



