MARINE MAMMALS OF THE NORTH-EAST OF SCOTLAND 67 



specimen had all the under parts white, and was black or 

 blackish above ; not " white above and black beneath " as 

 mentioned in Mr. Lydekker's book on British mammals. 

 Both the adults, male and female, that I found were black 

 all over ; but as proof that they are not even varietally 

 distinct, my young female had a good deal of white on the 

 sides and under parts. The male Mesoplodon had a good 

 many " corduroy " markings on the shoulders and belly ; 

 the adult female had none of these, but I think it would be 

 rash to say that this is a sexual difference, as the young 

 female had traces of these markings. 



The sternum of the male had six pairs of ribs attached 

 to it. The sternum of the female had only five pairs, and 

 was differently shaped from that of the male. I do not 

 think, however, that this is a sexual difference, as another 

 sternum of a male I examined more resembled that of the 

 female sternum. Here, then, is another case of " individual 

 variation." 



One marked sexual difference is always to be seen in 

 this species. The male has two large functional teeth in 

 the lower jaw, from which they project about 2 inches above 

 the gum. The female has only rudimentary ones, and these 

 are hidden half an inch below the surface of the gum, while 

 the half-grown female had 50 additional small dolphin-like 

 teeth present in both jaws. That is to say, there are, in 

 this young specimen, in addition to the two rudimentary 

 tusk-like teeth in the lower jaw, 17 small ones behind 

 them on each side, and 8 on each side of the upper jaw. 

 I believe a neiv genus was once founded on the presence of 

 similar rudimentary teeth in Mesoplodon. 



It may be interesting to state that the dorsal fin of the 

 male was placed nearly a foot farther back than that of the 

 female. Is this another "individual variation"? 



I have come to the conclusion that the male stranded in 

 1896, and the mother and young stranded in 1899, were all 

 members of one family. It was reported to me in 1896 that 

 the stranded whale was accompanied by another, and also a 

 young one, both of which got away. Now as this species is 

 over 5 feet long when born, one would expect it to grow 4 or 

 4.5 feet more in three years, say 18 inches per annum. The 



