268 DISCOVERY REPORTS 



examining the genitalia) the ovaries are examined, and if a functional corpus luteum 

 is present the uterus is searched from end to end for signs of a foetus. Before being 

 opened, however, if there is not a large foetus present, the width of the uterus is 

 measured across one cornu as it lies on the platform. After it is opened a note is made 

 if there is congestion of the internal wall, and in some cases a piece is preserved for 

 histological examination. 



The ovaries are examined in some detail. A full series of observations consists in 

 measurements of size and weight, counting all the corpora lutea, fresh and old, and 

 measuring each in three dimensions, and describing the condition of the Graafian 

 follicles and measuring the larger ones. It appears now, however, that if the presence 

 of a functional corpus luteum, the number of corpora lutea and the size of the largest 

 follicles are noted, the rest is not of much importance. 



Shortly after the internal genitalia become accessible the stomach is exposed by the 

 opening up of the carcass, and can be split with the touch of a knife. The possibility 

 of the stomach being damaged by the harpoon, and the contents thus escaping, has 

 to be borne in mind when it sometimes appears to be empty. 



The series of observations is usually brought to a close by a brief examination of 

 the intestines for internal parasites. Very occasionally it is possible in the final stages 

 of the dismemberment of the carcass to examine the degree to which the vertebral 

 epiphyses have fused with the centra. 



When work is finished at the whaling station any specimens are taken back to 

 the Biological Station and the notes are entered up in log-books. These are in the 

 form of large ledgers of which three patterns are kept. The first, for general notes, 

 has a double page for each whale, the pages being divided into a number of sections 

 in which notes can be made under the various headings such as colour, food, internal 

 genitalia, etc. In the second book all the measurements of bodily proportions are 

 entered, and in the third particulars of every foetus found, including bodily measure- 

 ments, external characters, etc. 



The primary difficulty of investigating the habits of whales is that it is almost impos- 

 sible to make direct observations on them. It is for instance impossible to keep one 

 whale or a group of whales under observation for any length of time and direct observa- 

 tions on their breeding habits have been few and far between. Indirect methods must 

 therefore be employed. By observations at whaling stations information is mainly 

 gained (apart from questions regarding specific identity) by studying the seasonal 

 changes which take place through the year in whales of the same species and sex and 

 in the whale population as a whole. For instance the changes which take place through 

 the year in the lengths of foetuses provide information on the seasons of pairing and 

 parturition and the rate of growth of the foetus ; the seasonal changes in the condition 

 of the reproductive organs give rather more direct evidence on the breeding season ; 

 the times of year at which ovulating and lactating females and young calves are most 

 abundant are to be examined in connection with the general sexual cycle; and the 

 movements and migrations of the whales are to some extent reflected in the seasonal 

 variations of the food and thickness of the blubber. 



