2 S o DISCOVERY REPORTS 



As Matthews has pointed out, there is no correlation between the number of teeth and the length 

 of body or other attributes of age. This applies equally to the number of teeth erupted and to the 

 total number including subcutaneous ones. A set of twenty-one mandibular teeth on each side could 

 be palpated below the gum in a 3-53 m. foetus examined in 1949, and those whales with uncut teeth 

 had sets, apparent as serial swellings along the gum (Plate I, fig. 6), of between twenty and twenty-five 

 a side. Those with erupted teeth usually had two or three, and one whale as many as six, subcutaneous 

 ones at the posterior end of the tooth row. In two whales, one male and one female, the extreme front 

 tooth of one side was still embedded in the gum. The largest erupted teeth are always in or near the 

 middle of the row, and I agree with Boschma (1938, p. 204) that Hunter was wrong in proposing 

 that teeth in sperm whales are added to the row from behind with increasing age (1787, p. 400). 



Table 9. Frequencies of the numbers of erupted teeth in whales examined at 



Horta in 1949 and 195 1 



No. of whales 



Data are available on the teeth of sixteen male and twenty-six female whales from Horta. In 1949 

 both unerupted and erupted mandibular teeth were counted, but the counts in 1951 were limited to 

 erupted teeth. Table 9 gives the frequencies of the numbers of erupted teeth, both maxillary and 

 mandibular, in the forty-two whales. The tooth row is seen to contain from sixteen to twenty-six 

 erupted mandibular teeth in males and from nineteen to twenty-six in females. Actually there is no 

 real sexual difference in the range, for inclusion of the unerupted teeth closes it to nineteen to twenty- 

 six for males and to twenty to twenty-six for females. The sexes also correspond closely in their 

 average tooth numbers. This may be seen in Table 10, which includes averages from Japan and from 

 the Southern seas as well as from the Azores. The figures for Japan are calculated from data given 

 by Omura (1950, p. 97), who has concluded from frequency diagrams that, in general, the number of 

 functional teeth is greater in males than in females. But the differences in Table 10, and also in his 

 frequency diagrams, seem too small to be significant. In Table 10 also, the figures for Azores and 

 southern whales (although from admittedly smaller samples) do not show, left and right, that the 

 male averages are consistently a little greater than the female ones ; some are a little smaller, which 



