1912-13.] Functional Teeth in Upper Jaw of Sperm Whale. 167 
or polished, apparently by friction : and the obvious conclusion was that, 
in this case, the maxillary teeth had been functional. 
A second visit to the whaling station at Bunaveneader in Harris in 
1912, for the purpose of obtaining a Sperm skull for the Boyal Scottish 
Museum, has resulted in even more convincing demonstration of the 
utility of the maxillary teeth. A single male Cachalot was captured and 
brought in during this visit, and it, fortunately, also bore exposed teeth, 
about a score in number, in the upper jaw. With considerable difficulty, 
after the breaking of a strong knife-blade and the final use of axes, made 
necessary by the density of the flesh, one of the teeth was excised along 
with the surrounding portions of gum, and this forms the subject of fig. 1. 
The maxillary teeth lay in a row along a well-defined groove running 
the length of the jaw on the inner side of the depressions caused by the 
mandibular teeth. Each tooth was situated near to, and on the inner and 
posterior side of, a mandibular pit, the inner margin of a pit being in- 
dicated by the curve behind the tooth in fig. 1. The exposed portion of 
the tooth presents in plan an oval section, but the sharp point common 
in maxillary teeth has been completely abraded, and on the flattened top 
the concentric arrangement of the dentine is clearly visible — a central 
translucent core surrounded by a ring of whiter and more opaque material. 
The surface is marked by fine grooves and scratches, additional evidence 
of its having been in use. 
The removal of part of the surrounding gum showed that, as is so often 
the case, the tooth was much twisted (fig. 2). It was 11 cms. long; and 
its curve approximated a quadrant of a circle, the fang, which was broad 
and jagged, being turned outwards so that it lay almost at the base of the 
mandibular pit, where it may have served as an opponent to the mandibular 
tooth. All hut the tip of the tooth was simply embedded in the gum, far 
removed from the maxillary bone itself. The stability of the tooth, 
however, was not affected thereby, for the consistency of the gum was so 
dense and ligamentous that it afforded a perfectly firm setting, as indeed 
also occurs in the case of the mandibular teeth, which in the specimen^, 
prepared for the Royal Scottish Museum were held in place by the gum,, 
the sockets in the lower jaw being far too wide and too shallow to grip the 
fangs of the teeth — a fact observed many years ago by Owen.* 
That the occurrence of functional teeth in the upper jaw of the Sperm 
Whale is rare, the negative results of the observations of many naturalists 
make clear ; but that it is not an abnormal phenomenon is equally apparent 
from the evidence furnished by two out of seven specimens examined by 
* Owen, Odontography , London, 1840-45, p. 354. 
