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I have before said that at the back of the head or occiput 

 there rises a sort of semicircular wall, almost perpendicularly. 

 This is formed by the right bone of the nose, the base of the 

 right intermaxillary, and the base of the two maxillaries doubled 

 by the occipital. The maxillary forms the anterior angle of the 

 orbit, in front of which it has a deep emargination or notch, and 

 close to this notch, on each side of the head, is a deep hole, which 



to refer to Dr. Alderson's paper. According to Sibbald, in the Blcacklish, a 

 little above the middle of the rostrum, " there is a lobe which is called the 

 lune, having two entrances covered with one operculum, called the /o^^ " 

 Now, from the relation which the position of the nostrils iu the skull bears 

 to that of their single external opening, or blow-hole, at the front of the 

 snout in the genus Catodon, we may infer that a blow-hole placed nearer 

 the middle of the head, as in the Blackfish, would not so much distort the 

 general appearance of the head. And here, by the way, I may observe, 

 that the words "spiracle" and "blow-hole" appear to be better uames 

 than "spouter" for that external orifice by which the canal from the 

 nostrils opens to the atmosphere ; particularly if Beale be correct, who 

 asserts that these animals never eject water from their nostrils, but only 

 vapour. No better external characteristic of the true sperm whales, or 

 genus Catodon, has yet been given than the position of their single blow- 

 hole at the summit of their snout — the "fistula in rostro" of the old 

 naturalists. It is as good a character as their fat quadrangular snout 

 itself. And were it not that the Blackfish, or genus Physeter, is said to 

 have the blow-hole at the middle of the snout, as another cetacean of the 

 same family, hereafter to be described, most certainly has likewise, all the 

 C'afodontidir, or family of sperm Avhales, might thus be neatly separated 

 from dolphins. The genus Catodon agrees with the herbivorous Cataa-a 

 alone, in having the nosti'ils opening at the extremity of the snout. It is 

 not the object of the present work to enter particularly upon the external 

 appearance of sperm whales, or upon the anatomy of their soft parts. 

 Indeed, as yet, I have had few opportunities of studying such subjects. I 

 may remark, however, that nothing is certainly known of the mode in 

 which the single spiracle of the sperm whales communicates with the two 

 nostrils in the skull. John Hunter would seem to assert, that there is only 

 a single tube or canal from the commencement, for both nostrils. In some 

 dolphins, on the other hand, there is said to be a dividing membranous 

 septum. But all this subject requires further investigation ; the only thing 

 which appears certain being, that their single external si^iracle proves the 

 Catodontidte to be rather dolphins than true whales, which last have two 

 distinct external spiracles, communicating by separate canals with the holes 

 in the skull. 

 C 



