224 PROFESSOR FLOWER ON THE RECENT ZIPHIOID WHALES, 
lumbar 12, caudal 19; total 48. This appears to be very nearly the usual number in 
Ziphius and Mesoplodon, and to exceed that of Hyperoodon by 3. 
Though generally resembling that of the three allied genera, the column differs from 
Mesoplodon sowerbyi (Van Beneden and Gervais, pl. 22) chiefly in the spines of the 
anterior dorsal region being smaller, more pointed, and more recumbent—also in all 
the other spines sloping more backwards, and being smaller in proportion to the body, 
both in height and width from before backwards; thus in a middle lumbar vertebra, 
the antero-posterior diameter of the spine in Sowerby’s Dolphin is about two thirds 
the length of the body, while in Berardius it is little more than one third. /. densi- 
rostris and another as yet undetermined species in the Sydney Museum agree generally 
with WM. sowerbyi in these respects, judging from photographs of their skeletons sent by 
Mr. Krefft. Ziphius australis appears in Burmeister’s figure to be rather intermediate 
between Mesoplodon and Berardius in the form of the spines of the vertebre. In 
Hyperoodon the spines are as long as in Mesoplodon and as slender as in Berardius. 
Cervical Vertebre.—Vhe vertebre of the neck (Pl. XXVIII.), especially those of the 
posterior part of the region, are better developed than in most Dolphins, and, indeed 
(except for the coalescence of the first three), bear a considerable resemblance to those 
of the Beluga. Among the Ziphiine, as far as is yet known, Mesoplodon and Ziphius 
both approach Lerardius in the structure of this important region, while, as will be 
seen, /Hyperoodon offers the greatest possible contrast. 
The entire length of the bodies of the seven cervical vertebrae, when placed in con- 
tact, is 10 inches. The atlas, axis, and the third vertebra are united firmly by their 
bodies; and the first two are also united by the lamine of the neural arches, but the 
axis and the third only by that portion of the arch corresponding to the zygopophyses, 
the upper part being free. All the remaining vertebra are separate throughout. The 
free ends of their bodies show traces of the epiphyses by which they have been com- 
pleted; and their surfaces appear so completely formed or finished, as it were, that it 
does not appear probable that much, if any, further union would have taken place had 
the animal attained a greater age. 
In Hyperoodon not only is the whole length of the cervical region scarcely more than 
half that of Berardius, but the bodies of all seven vertebre are firmly united together, 
and the spines of all, except the seventh, join to form a single elevated conical mass ; 
the vertebra, except the first two and the last, are evidently extremely compressed, 
almost rudimentary in fact. In Ziphius australis, according to Burmeister, the first, 
second, and third are united, and also the fourth and fifth to each other, though not to 
the third, and the sixth and seventh are free. In the specimen of Ziphius cavirostris, 
from Corsica, briefly described in Fischer's memoir, the six anterior vertebre are stated 
to be united and the seventh free. In Sowerby’s Mesoplodon at Brussels the first two 
only are united, and all the others free. In JZ. densirostris, according to Krefft’, “the 
1 P. Z. 8. 1870, p. 426. 
