Bibliographical Notices. 193 
backward ; and the olecranon projects conspicuously beyond both the 
ulna and humerus. ‘There are five carpal bones, three forming a 
large proximal row below the epiphyses of the ulna and radius, and 
two small bones forming a lower row. These carpals are named 
the naviculare, lunatum, triquetrum, hamatum, and capitulum. 
There are four digits, which correspond to the second to fifth. The 
second is slender and contains five bones, the third stout, with six 
bones; the fourth has five bones, all stouter than those of the 
second; while the fifth digit has four bones, which rapidly diminish 
in size. ‘The hinder extremity is represented by a single bone, pro- 
bably pelvic, but of somewhat unusual form, though most like the 
pelvic bone of Balenoptera rostrata. The hyoid is very similar to 
that of the North-Atlantic species. 
The second species, Balenoptera patachonica, is described from a 
perfect specimen, obtained in 1871, which was 50 feet long. Its 
form was more slender than the species just described, and closely 
resembles the Balenoptera nvusculus, but was unfortunately stripped 
of flesh before seen by the author. He remarks on the differences 
which this skeleton shows from an imperfect specimen which was in 
the museum before it came under his direction, and is disposed to 
‘attribute the differences to sex and age. The skull is described in some 
detail, and the figures demonstrate its difference from other Argentine 
species; but Dr. Burmeister has been limited to the use of figures in 
comparing it with the northern form, which it most resembles. The 
first found specimen, which was figured in the ‘ Proceedings of the 
Zoological Society’ for 1865, and which may therefore claim to be 
the type, differs, so far as can be judged from the figure there given, 
to an inconvenient degree from the new type now figured. The 
'vomerine bones of the second specimen extend further forward than 
in the first type; but in that type the frontal bones extend further 
outward, so as to cover and hide the jugal bones, the nasal bones are 
narrower and longer, the notches external to the occipital condyles 
are deeper, and the snout tapers forward ina manner more marked. 
Other differences no less obvious are to be detected in the representa- 
tions of thevertebree and scapula; so that the species must be regarded 
as extremely variable ; and this circumstance is suggestive of the pro- 
bability that more abundant materials would do something towards 
blending it with the northern species, to which Burmeister indicates 
its affinity. 
In his account of the neck the author restricts himself chiefly 
to establishing the differences between the vertebree of the three 
species which he describes. ‘he atlas of the Balenoptera pata- 
chonica has the occipital facets too close together to receive the den- 
tata between them as in the other species ; and the form of the neural 
arch is distinctive of the axis in all three. The form and arrange- 
ment of the transverse processes differ considerably in the later 
cervicals. The length of the neural spine, as usual, is very little in 
the cervical region ; but in the dorsal region it soon attains a con- 
siderable elevation, though relatively shorter than in the Baleno- 
_ ptera bonaérensis. The height of the neural spine still increases a 
Ann. & Mag. N. Hist. Ser. 5. Vol. xii. 14 
