8o 



WHALES 



Figure ^g. Four teeth {mol- 

 ars with two roots) of a 

 Squalodon from the Mio- 

 cene deposits of Belluno, 

 Italy {about /j million 

 years old). {De ^igno, 

 1876.) 



descend again from the afterdeck, and we can use the (opportunity to inspect 

 a few other pecuharities also. The umbiHcus is generally fairly distinct, and 

 a little anterior to the small slit hiding the retractile penis. The female 

 genitalia open much nearer to the anal vent, i.e. much further tailwards 

 (Fig. 42). 



As we examine our whale, we are immediately struck also by a series 

 of parallel grooves running longitudinally on the lower surface of the 

 throat and chest region, from the jaw to the umbilicus. The grooves are 

 al)out 2 inches deep, and are separated by ridges 2^-3^ inches wide (cf. 

 Fig. 135). In the case of the Grey Whale, we find no more than a few 

 grooves under the throat, and Right Whales have no grooves at all. 

 Rorquals, on the other hand, have 40-100 of them. 



Figure 40. Top view of the 

 skull of a female Narwhal, 

 showing its asymmetrical 

 construction. { Van Beneden 

 and Gervais, 1880.) 



