424 ZOOLOGY. 
spectator be placed at .quite a considerable distance, many mistakes might 
readily have been introduced into drawings, which are, with a few excep- 
tions, the only data in our possession. Thus, the small spermaceti (P. cato- 
don), the blunt-headed cachalot (P. trwmpo), the round spermaceti whale 
(P. cylindricus), the small-eyed cachalot (P. microps), the great-finned 
eachalot (P. mular), and the bunched cachalot (P. gibbosus), are still doubt- 
ful species; the two-toothed cachalot of Sowerby (P. bidens sowerbyt) belongs 
to the family of Heterodonts, but is not sufficiently known to decide upon 
its real place. It constitutes a genus by itself, nearly allied to Delphinus 
proper, with a peculiar organic structure, uniting Physeteridee to Delphinidee 
more intimately than any other group. 
The fishing grounds for the spermaceti whale are from the Seychelles 
Isles to Timor, and all the coast of New Holland as far as Shark’s Bay, the 
Japanese seas as far as the Philippine Isles, and to the eastward as far as 
California. 
The fossil remains of Physeter, which have already been discovered, 
have not been made the subject of a careful examination. Fragments were 
obtained in France and England, and, we are told, also in North America ; 
but the specimens alluded to here, and upon which the genus Wephrosteon 
has been established, are said to belong to:a recent and still living species. 
The generic name Arionius has, however, been given to a skull disco- 
vered in the meiocene of Germany. The upper part of its posterior surface 
is concave, and along the middle a vertical ridge is seen, vanishing as it 
goes downwards; the forehead is flat, horizontal, and remarkably broad, 
decreasing gradually in the elongated snout; the sides, formed by the tem- 
porals and frontals, are very concave from above downwards; the nasal 
canal widens in its way along the snout; the jaws are armed with numerous 
teeth; those on the lower jaw are longer and more acute, with almost 
rounded roots, and the crown pointed, conical, scarcely bent, provided in 
front and behind with a sharp edge, whilst on the sides a slight, not quite 
regular furrow is to be seen. A single species (A. servatus) is described. 
This genus may perhaps prove hereafter to belong to the next family, or 
even an intermediate between both the latter and this. 
The genus Balenodon is known by a single fragment of a tooth, whose 
structure differs from the same parts in Physeter in eves the dene layer 
thicker. The species is designated under the name of B. physaloides. 
. Fam. 3. DELPHINIDA, constitutes a very natural group among Cetacea. 
It is composed of the smallest species of the order, although some of them 
attain a considerable size, as between twenty-five and ee six feet in 
length. The dolphins have a fusiform body, which seems completely 
deprived of a neck, the anterior region of which terminates by a snout 
more or less elongated, whilst the posterior region, the tail, is terminated 
by the horizontal fin common to all Cetacea. The size of the head is not 
disproportionate when compared to the body. The jaws are nearly of 
equal length, and both are furnished with a row of more or less conical or 
compressed teeth, varying in number in the particular species. ‘They are 
developed on the margin of the maxillaries, and in some species inserted in 
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