THE SOUTHERN SEA LION 151 



low columnar and pycnotic nuclei are plentiful. The glands are few and straight, being 

 much reduced, although secretion may still be present. The blood vessels are small. 



Summary of history of the sterile cornn 



In the earlier part of pregnancy the epithelium declines from a fairly tall columnar to 

 a cubical type but again rises to low columnar. The glands decrease in activity as preg- 

 nancy progresses, the central parts first becoming ductlike, a condition which spreads to 

 the peripheral parts. Secretion is still in progress when the foetus is about 15 cm., but 

 about this time the epithelium is much exhausted and the glands eventually decrease 

 in size and complexity until with the 53 cm. foetus they are few in the section and 

 straight, although even at this stage some secretion may be present. Blood vessels are 

 large and numerous at a foetal length of 10 cm., but they also diminish so that when the 

 foetus is 53 cm. they are few and small. The final condition, except for the slightly 

 increased height of the epithelium, resembles that of the anoestrous uterus. 



PUBERTY 



The female becomes sexually active during the fourth year, not "about the end of the 

 fourth year" as previously stated (1934, p. 297). In addition to the five fourth year cows 

 of the 1930-2 series nine others were collected in 1933-7, and of them three had no 

 corpora lutea in the ovaries, and whereas two (nos. 458, 512) had follicles over 0-9 cm. 

 in diameter, the third (no. 450), which was the largest of the three, was in a quite inactive 

 condition, not yet having begun ovulation. 



Two of the nine (nos. 509, 511) were pregnant and the remaining four (nos. 417, 

 419, 423, 490) had ovulated, since each had a corpus luteum: no trace of previous 

 corpora lutea was found in any of these four. It seems quite probable that the corpora 

 lutea of these four cows were derived from first ovulations. 



These nine cows were collected at different dates in January, February, June, July 

 and September. 



Having regard to the above it is my opinion that this animal begins to ovulate in its 

 fourth year, sometimes so early as to permit of successful impregnation (nos. 509, 511), 

 but perhaps more frequently in winter, or later. It should be assumed that the virgins 

 are served for the first time at the age of four years. 



SENILITY 



The oldest age group consists of 18 seals of the tenth year or over and specimens from 

 the genitalia of 14 have been preserved. 



It is but reasonable to believe that this class extends beyond the tenth year, since two 

 females of this species lived for 15^ (not i6\ as in Hamilton, 1934) and 17^ years in 

 captivity and the latter was believed to be about two years old on arrival in London, 

 but since that was in May she must have been about sixteen months or twenty-eight 

 months old and must therefore have been almost nineteen or twenty years of age when 



she died. 



Sections from five of the 13 uterine specimens exhibit in both cornua the hyalinized 



