382 DISCOVERY REPORTS 



One must conclude that these three types of aberrant corpora are very similar in size and structure 

 and, therefore, in their origin and fate. In fact they may represent stages in the regression of one type. 

 It is noticeable that all are more or less avascular bodies and appear to have undergone a type of lipid 

 hyaline degeneration which is probably a direct result of the deficient vascularization. 



It is not possible to say with certainty whether they persist as well-pigmented bodies for a long or 

 short period. Nor is it known at which part of the breeding cycle they are formed, but they do not 

 represent corpora lutea of pregnancy. All three types are found in females at puberty in addition to 

 the more usual corpora albicantia. It seems likely that in fully mature females they form during or 

 prior to the resting period and possibly again as accessory corpora lutea at the start of pregnancy. 

 These bodies are present in 38-4± 19-0% of resting females and i3'2±7*4% of pregnant females, but 

 this difference is not quite significant at the 95 % level. In the first half of pregnancy (foetus 0-1 m. 

 long) 45 ±30% had one or two such bodies in the ovaries, and in the second half of pregnancy (foetus 

 larger than 1 m.) only 7- 1 ± 5 -8 % had corpora aberrantia in the ovaries. Of those females with foetuses 

 longer than 2 m. only 1-7 ±3 -7% had such corpora. Of eleven lactating females none had such 

 corpora aberrantia; some lactating females have anomalous corpora which are like corpora albicantia 

 in their gross morphology but resemble corpora aberrantia in their histology. These observations 

 suggest that their longevity as corpora aberrantia is probably little more than a year, and if some are 

 formed at the same time as the corpus luteum of pregnancy then their life is only about 6 months. 

 Their scarcity in terms of total corpora (1-4%) and their relative abundance in terms of the proportion 

 of ovaries showing them (12-5%) supports this contention. In view of the fact that 38-4±i9 # o% of 

 resting females had corpora aberrantia in the ovaries, but no lactating females had them, it would 

 seem likely that these resting females had ovulated recently. 



Corpora aberrantia are unlike corpora albicantia in their morphology, but the appearance of the 

 collagen is similar to the pigmented collagen of corpora albicantia, except that it is much more heavily 

 laden with lipids and pigment and the distribution of lipoid material is different. In view of their 

 collagenous nature they cannot be regarded as functional, but are regressing bodies. 



Corner, Bartelmetz and Hartman (1936) concluded that the corpora aberrantia, which they 

 described in the rhesus monkey, were probably formed at the same time as corpora lutea of the cycle 

 or of pregnancy. The whale corpora aberrantia now described are different from those described by 

 Corner, Bartelmetz and Hartman which retain recognizable granulosa lutein cells and have a very 

 noticeable network of capillaries. The latter are also much larger relative to the true corpora lutea 

 than are the whale corpora aberrantia. These authors' type 3 corpora aberrantia appear to be very 

 similar to the whale corpora atretica to be described below. 



In most respects but size, the whale corpora aberrantia appear to agree with the description by 

 Dubreuil and Riviere (1947, p. 83 and fig. 27, 1) of the ' mode de degenerescence lipoide ' in the human 

 ovary. 



Corpora atretica 



In addition to the corpora lutea, corpora albicantia and corpora aberrantia, there are in fin-whale 

 ovaries a number of small, bright orange-pigmented bodies. Laurie (1937, p. 244) described occasional 

 yellow bodies in blue-whale ovaries. These were small (1-0x0-3 cm -) an d located deep in the ovary 

 as compared with the other types of corpora which are most superficial. They were described as 

 corpora atretica, the relics of atretic follicles. In the sample of fin-whale ovaries with altogether 

 2655 corpora lutea, albicantia and aberrantia there were a further 5% of corpora atretica. The 

 greatest numbers were found in resting females (maximum 4) and in pregnant females with a foetus 

 1-3 m. long (maximum 8). In contrast to the corpora aberrantia no significant differences were found 

 in the percentage occurrence of corpora atretica at different stages of the sexual cycle. 



