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into the base of the beak for If inch beyond the pre-maxillary 
foramen, whilst in the skull in the Museum of Science and Art it 
did not extend more than half an inch. The pre-maxillary foramen 
was immediately in front of the maxillary foramen in both speci- 
mens, and the lateral border of the base of the beak was in both a 
sharp ridge and not grooved. In the Shetland specimen the meso- 
rostral bone was fused both with the vomer and the pre-maxillse, 
though grooves on the surface showed the line of demarcation from 
the premaxillse. The meso-rostral bone became attenuated anteriorly, 
and ended in a fine point immediately behind the broken end of the 
beak. In the type skull in the Oxford Museum, if I may judge 
from a cast of that specimen, the ossification of the meso-rostral 
cartilage had extended very completely for nearly 6 inches in front 
of the mes-etlimoid, and less completely for 3 additional inches. 
The presence of a meso-rostral bone and of large mandibular teeth 
are therefore characteristics of the adult male. The vomer, where it 
appeared mesially on the under surface of the beak, was somewhat 
thicker than in the skull in the Museum of Science and Art. The 
tympanic bones were lost, but the left petrous bone was preserved. 
It closely resembled the petrous bone of Mesoplodon layardi figured 
by me in the Reports of H.M.S. “ Challenger.”* 
The pair of mandibular teeth projected nearly 2 inches beyond 
the alveolus. They were triangular and laterally compressed. The 
anterior border sloped very obliquely forward ; the posterior border 
was almost vertical. The surface of the fang was rough, with 
ridges passing obliquely downwards. The crown was smooth, ter- 
minating in a point, and was separated from the fang by a well- 
marked line. Each tooth was partly opposite and partly imme- 
diately behind the posterior end of the elongated symphysis. A 
groove in the alveolar border of the bone passed for 2 inches back- 
wards behind the erupted tooth, and in it rudimentary denticles had 
at one time probably been lodged. 
The discovery by Professor Reinhardt of a row of rudimentary 
functionless teeth on each side of the upper jaw of his specimen of 
Mesoplodon bidens , is of great interest. The New Zealand Meso- 
plodon grayi , mainly on the possession of a row of minute teeth in 
the upper jaw, has been made, by Dr. Yon Haast, a new genus, 
* Keport on tlie Bones of Cetacea, pi. i. fig. 5, Zoology, vol. i. 1880. 
