1864.] IN THE MUSEUMS OF HOLLAND AND BELGIUM. 389 
No costo-sternal bones. All the ribs at their upper extremity arti- 
culating only with the transverse processes of the vertebrz ; their 
eapitular processes, when developed, rudimentary, and not forming 
true articulations with the bodies of the vertebrae. Rami of mandi- 
ble curved, their anterior ends meeting at an angle, and connected 
by fibrous tissue, without any true symphysis. Skull symmetrical. 
Maxilla produced in front of, but not over, the orbital process of 
the frontal. Nasal bones well developed, symmetrical. Lachrymal 
bones distinct from the jugal*. 
If. DeLeuinoipea. Teeth always developed after birth, and ge- 
nerally numerous, sometimes few and early deciduous. No baleen. 
Sternum elongated, composed of several pieces placed one behind the 
other, to which are attached the ossified cartilages of several pairs of 
ribs. The anterior ribs with capitular processes developed, and arti- 
culating with the bodies of the vertebrae, as in other Mammalia. 
The posterior ribs without head, and only articulating with the trans- 
verse processes. Rami of mandible straight, the two coming in con- 
tact in front by a surface of variable length, but always constituting 
a true symphysis. Upper surface of the skull generally, if not 
always, unsymmetrical. Upper end of the maxilla expanded, and 
produced over the orbital process of the frontal bone. Nasal bones 
rudimentary and unsymmetrical. Lachrymal bone confluent with 
the jugal. 
In conforming with all the above characters, the Sperm Whales 
are true Delphinoids ; but into the further divisions of this group I 
do not at present propose to enter. 
The Balenoidea tall naturally into two families, the Balenide or 
Leiobalene (Eschricht), Smooth Whales or Right Whales, and the 
Balenopteride or Ogmobalene (Eschricht), Furrowed Whales or 
Rorquals. 
1. The Balenide have a very large head (exceeding one-fourth 
of the total length of the body) ; no dorsal fin; the under surface 
of the throat and chest smooth. The bones of the cranium greatly 
arched, so as to leave a wide interval between the upper and lower 
jaws. The rostrum narrow and compressed at the base. The or- 
bital processes of the frontals very much prolonged, and extremely 
narrow and rounded on their upper surface. 'Tympanic bones broad, 
thomboid. The coronoid process of the lower jaw scarcely percept- 
ible. Baleen-plates long and narrow. All, or the greater number of 
the cervical vertebrze ankylosed together. Hand broad and penta- 
dactylous. 
The members of this family are not sufficiently distinguished from 
* The statements, in works of comparative anatomy and zoology, regarding 
the lachrymal bone of the Balenoidea, afford a curious example of the difficulty 
of eradicating a mistake when once it has become incorporated in scientific lite- 
rature. The defective condition of most of the skulls preserved in museums was 
undoubtedly the original source of error; but, notwithstanding Cuvier’s distinct 
description, in the skull of the Rorqual, of the bone ‘‘ qui ne peut étre que l’ana- 
logue du lacrymal” (Oss. Foss., edit. 1836, t. viii. p. 275), the absence of the 
lachrymal is repeated as a character of the section in many of our most valued 
treatises. 
