THE HUMPBACK WHALE 



39 



this value, but are too scanty to allow one to conclude definitely that the southern 

 Humpbacks have more ventral grooves than the northern ones. 



Table XII. Humpback whale. Numbers of ventral grooves 



At the posterior end the median grooves run back to the umbilicus, while the lateral 

 ones are progressively shorter the farther they are from the median line. Between the 

 umbilicus and the genital aperture, especially in females, there is frequently a short, 

 transverse, curved groove arranged with its convexity directed forwards (Fig. 40). On 

 the other hand. Fig. 41 shows a shallow median groove joining the umbilicus to the 



Umbilicus 



Vulva 



Umbilicus 



Genital Groove 



-A, 



nus 



Fig. 40. Humpback whale. Female. Transverse 

 curved groove between umbilicus and genital 

 aperture. 



Fig. 41. Humpback whale. Male. Shallow median 

 groove joining umbilicus and genital groove. 



genital aperture in a male. One or two irregular shallow grooves may be present in the 

 female, on each side of the mammary grooves. At the anterior end of the series the 

 grooves towards the centre join together in the middle line short of the chin, while the 



