6 ANNALS OF SCOTTISH NATURAL HISTORY 



The length of the mandible in Physeter inacrocephalus 

 was taken in the way adopted by Sir William H. Flower. 1 

 A line was drawn between the backs of the two condyls, 

 and from its mid-point a straight line was drawn to the tip 

 of the jaw. It should be stated that the jaw had probably 

 been two inches longer than the measurement obtained, as the 

 most anterior tooth socket on each side had been broken across. 



When these measurements are compared with those 

 given by Sir William Flower in his account of the mandibles 

 of sperm whales in the Museum of the Royal College of 

 Surgeons of England, it will be seen that the Edinburgh 

 specimens compare favourably with the largest mandible 

 from Tasmania in that Museum, and show that they were 

 from animals which had reached adult life and were of great 

 magnitude. 



Sixty-four teeth were sent to me. Of these, forty-two 

 were undoubtedly mandibular teeth from their conical shape, 

 the size and depth of the pulp cavity, and the polished, 

 partially worn and somewhat flattened surface of the summit 

 of the crown. The longest of these teeth was 193 mm. (7.6 

 in.), and the one with the greatest circumference was 200 mm. 

 (almost 8 in. in girth). The shortest tooth which showed 

 evidence of being worn was 109 mm. (4.3 in.) in length and 

 only 80 mm. (3.3 in.) in circumference. 



Of the remaining twenty-two teeth it was difficult to say 

 definitely whether seven were or were not mandibular, though 

 probably some of them were; they varied from 104 mm. 

 to 85 mm., and the greatest circumference was 77 mm. 

 Five had shallow pulp cavitives, but in the two others the 

 cavity was obliterated by dense tooth tissue, perhaps crusta 

 petrosa. No specimen had the summit of the crown polished 

 or worn, but the tip was roughened and somewhat jagged. 

 Obviously they had never cut the gum or been subjected to 

 friction ; if mandibular, they had been at the hinder end of 

 the dentary arcade, where the dental groove in the jaw is 

 shallow and the sockets for the teeth are comparatively 

 faintly marked. 



The remaining fifteen teeth had in part, if not altogether, 



1 'Osteology of the Cachalot or Sperm Whale,' " Trans. Zool. Soc. Lond.," 

 vol. vi. part vi. p. 320, 1868. 



