356 



WHALES 



Figure igy. Section of vagina of a porpoise, 

 showing annular folds, resembling funnels 

 with their mouths directed towards the 

 cervix (C). {Pycraft, 1932.) 



on the meteorological ship Cumulus, who, on i8th 

 April, 1959, observed a school of about twenty Pilot 

 Whales at love play close to the ship, which was then 

 at 52° N., 20° W. Every so often, five or six animals 

 would surface vertically right up to their pectoral 

 fins, while other pairs would swim side by side, 

 occasionally biting each other's mouths playfully. 

 They would then dive under and assume an almost 

 hoiüzontal position, belly to belly. After about twenty 

 seconds, one or both partners would emerge verti- 

 cally out of the water (see Fig. 196 and p. 187). 



While all the available evidence, therefore, indi- 

 cates that Cetaceans copulate veiy quickly, reliable 

 data are still scarce. Biologists would much welcome 

 any further information on this subject gathered at 

 first hand. 



In all Cetaceans, the external female genitalia 

 are contained in an elongated genital slit, just anterior to the vent 

 (Fig. 42 and 213). While the outer part of the vagina is smooth and contains 

 some longitudinal folds, lined with vaginal epithelium, the interior part 

 is provided with a number of prominent annular folds (Figs. 197 and 198), 

 which give the vagina the appearance of a chain of successive funnels with 

 their mouths directed towards the cervix. While their exact function is 

 by no means clear, these peculiar folds, which are not found in any other 

 mammals, may serve for keeping water out of the womb, and also for pro- 

 viding extra space to allow the foetus to be born. They may also play 

 some part during copulation. 



Like that of terrestrial mammals, the uterus of most Cetaceans protrudes 

 into the vagina by means of a snout-like cervix (Figs. 197 and 198) 

 provided with a very thick and rigid wall, thus causing the passage to the 

 uterus to become very narrow and very twisted, and the uterus to be 

 practically sealed off. (Narwhals and possibly Beaked Dolphins, as well, 

 are said to lack a definite cervix.) The uterus itself consists of a short 

 corpus dividing into the two uterine horns, which run parallel for a short 

 part of their length, and then bend respectively to the right and the left, 

 curving first upwards and then downwards, to continue as the oviducts 

 (Fig. 198). The oviducts, which receive the ova formed in the ovaries 



