THE HUMPBACK WHALE 6i 



the corpus luteum /; being too large to be that of a previous pregnancy. The scars in one ovary may 

 indicate corpora kitea b of previous sexual cycles or pregnancies, but the whale was badly decom- 

 posed and no further observations on the ovaries or on the mammary glands are available, so that 

 this point cannot be ascertained. 



No. 345. Length 12-6 m. 13. i. 26. South Georgia. Resting. One ovary contained a corpus 

 luteum b noted as "rather large". There were numerous follicles up to 20 mm. in diameter beneath 

 the surface. The whale was not lactating. The vulva was somewhat swollen and the uterus measured 

 26 cm. across. This whale had, then, recently reached maturity, but had missed pregnancy at the 

 first ovulation of the first sexual cycle and was in dioestrus preparatory to ovulating for the second 

 time. 



No. 355. Length 13-1^ m. 13. i. 26. South Georgia. This whale was very rotten, but was noted 

 as not lactating. 



No. 373. Length 12-^ m. 18. i. 26. South Georgia. Pregnant. One ovary contained a corpus 

 luteum a of mean diameter 10-5 cm., and one corpus luteum b of 4-4 cm. ; it weighed two pounds. 

 The other ovary had no scars and no follicles showing. Ovaries are noted as "very small". The 

 whale was pregnant, but the foetus had been lost subsequent to capture and the membranes only 

 were found. The vulva was slightly congested and not completely closed. The whale was not lac- 

 tating and the mammary grooves were closed. The corpora lutea and the length of the whale showed 

 that this whale had recently reached maturity and had become pregnant at the second ovulation of 

 the first sexual cycle. 

 . No. 3569. Length 1272 m. 18. i. 31. South Georgia. Pregnant. One ovary weighed i lb. 12 oz. 

 and contained a corpus luteum a of mean diameter 7-8 cm. and 9J oz. weight. It also contained 

 corpus luteum b of mean diameter 2-5 cm. The other ovary weighed eleven ounces and contained 

 no corpora lutea. No follicles were visible in either ovar>'. The whale was pregnant with a foetus 

 0-28 m. in length. The uterus was 22 cm. across the pregnant cornu, and 16 cm. across the non- 

 pregnant one. The mammary gland was 4 cm. thick and had never lactated. This whale was therefore 

 a young adult that had become pregnant at the second ovulation of the first sexual cycle. 



No. 3573. Length 13-5 m. 18. i. 31. South Georgia. Pregnant. One ovary weighed 3 lb. 10 oz., 

 and contained a corpus luteum a of 13 cm. mean diameter and 2 lb. 5 oz. in weight. It contained 

 five corpora lutea b of mean diameter 5, 4, 3-5 cm. and less. Some small follicles were visible below 

 the surface. The other ovary weighed i lb. 8 oz. and contained five corpora lutea b of mean diameter 

 6-5, 3, 3 cm. and less. The whale was pregnant with a 0-7 m. foetus. The non-pregnant uterine 

 cornu was 22 cm. across. The mammary gland was 5 cm. deep and involuted. This whale had there- 

 fore been pregnant at least once before, and probably more than once. 



No. 386. Length 18-5 m. 20. i. 26. South Georgia. Pregnant. One ovary weighed four pounds 

 and contained a corpus luteum a of mean diameter 9-5 cm. and four corpora lutea b of mean dia- 

 meter 4-5, 3, 2-2 and 1-2 cm. Some follicles up to 20 mm. in diameter were present. The other ovary 

 contained two corpora lutea b of mean diameter 3-2 and 1-7 cm. It contained one follicle 15 mm. in 

 diameter and some smaller ones below the surface. A foetus 0-38 m. long was present. The whale 

 was not lactating, but the mammary gland is noted as "well developed", which, with the state of the 

 corpora lutea, almost certainly indicates that it was involuted and that the whale was a multipara. 



No. 387. Length 13-55 ^n- 20. i. 26. South Georgia. Pregnant. One ovary contained a corpus 

 luteum a and one corpus luteum b. The other contained three corpora lutea b. A foetus 0-85 m. long 

 was present. No further data are available. This whale had probably been pregnant at least once 

 previously. 



No. 388. Length 13-55 m. 20. i. 26. South Georgia. This whale was badly decomposed but is 

 noted as not pregnant. 



No. 7487. Length 12-8 m. 2. ii. 26. South Georgia. Pregnant. No observations on the ovaries 

 are available. A foetus 0-5 m. long was present, and there was mucus in the vagina. The mammary 

 grooves were closed and the gland is noted as "well developed ". This probably means that the gland 



