. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. CETACEA. 567 apparatus of the nostrils. In order to consti- tute this part, one of the processes inclines towards the other, so as almost to come in contact with it for the two anterior thirds ; but posteriorly they recede from one another to give passage to the blow-hole. The cavity beneath this singular bony pent-house is occupied by an interlacement of numerous osseous pro- cesses, and by a close and hard fibrous sub- stance.* If we suppose the cranium of a Dolphin to be proportionally very much shortened, the margins
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. CETACEA. 567 apparatus of the nostrils. In order to consti- tute this part, one of the processes inclines towards the other, so as almost to come in contact with it for the two anterior thirds ; but posteriorly they recede from one another to give passage to the blow-hole. The cavity beneath this singular bony pent-house is occupied by an interlacement of numerous osseous pro- cesses, and by a close and hard fibrous sub- stance.* If we suppose the cranium of a Dolphin to be proportionally very much shortened, the margins of the rostrum to be greatly expanded and raised, so as to render its superior surface concave; the supra-frontal portions of the maxillary bones to be much developed and the margins extended upwards, thus form- ing an immense basin, at the bottom of which lie the external orifices of the bony nostrils ; if also the occipital crest in the Dolphin were raised behind the maxillaries so as to aid them in the formation of the bony cavity, in the basis of which the parietals are almost con- cealed, we should then have the skull of a Cachalot. The rostrum in the Catodontidtf, not- withstanding its immense size, is formed prin- cipally by the maxillary bones, as the inter- maxillaries and the vomer constitute a compa- ratively small part of the intermediate portion. The nasal passages extend obliquely from below upwards and forwards, but are of very unequal dimensions, the one on the right side not having one-fourth the breadth of that on the left. A corresponding want of symmetry is shown in the nasal bones themselves, and the cranium generally; and this circumstance, it may be remarked, characterizes in a greater or less degree the skull in all the Zoophagous Cetacea. The skull in the Whalebone-Whales fBaltz- nid<e) is, however, the most symmetrical in its general form; it is characterized by the great relative predominance of the facial over the cranial portion, by the narrown
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