114 PROF. W. B. BENHAM ON THE [May 21, 



enumerates the pouches present in the White Whale. Huxley's 

 account is descriptive but not illustrated ; and, unfortunately, his 

 account does not agree with Sibson's in regard to the point of 

 origin of the sacs; so that I am in some doubt whether my 

 conclusions as to the interpretation of the " upper chamber " (A) 

 are correct or not. In the Porpoise there are five pouches, two 

 pairs and an unpaired one ; in the White Whale two pairs only ; 

 in the Grampus seven pouches in all. 



According to Sibson the fire pouches in the Porpoise all com- 

 municate W'ith the " vestibule" above the openings of the narial 

 canals into that cavity. He writes : — " Connected with the 

 channel [i. e. vestibule] that leads from the external opening 

 [blowhole] down to the two bony conduits [^. e. narial canals] is a 

 series of pouches."' 



His figures indicate, but do not show quite clearly, that the 

 pouches are outgrowths of the vestibule, with w-hich they com- 

 mimicate above the entrance of the narial canals. 



On the other hand, Huxley in his ' Manual ' describes for the 

 Porpoise the " spiracular chamber " (i. e. vestibule) as receiving 

 the two nasal passages, the openings of which are guarded by 

 valves ; and then goes on to say that " Each nasal passage, after 

 it ceases to be surrounded by bone, sends off two diverticula, one 

 forward and one backward." 



The accounts given by the other authors referred to do not aid 

 us in deciding which of these two accounts is correct. But, 

 apart from this point of disagreement, all accounts agree that the 

 various pouches are, in the Delphinida?, not dilatations of the 

 canal but diverticula, either of the narial canal or of the 

 " vestibule." 



With regard to the " upper chamber " in the present Whale, it 

 is a possible view that it is the " vestibule," asymmetrically 

 expanded towards the right side, receiving the large left narial 

 canal near the external '• blowhole," and the small right narial 

 canal deeper down : in other words, that the slit carried by the 

 prominent papilla in the floor of the " upper chamber " is the 

 true right nostril. The chief facts that seem to me to be opposed 

 to this contention is that this " upper chamber " has a thin, grey 

 wall, and is devoid of that black pigmentation that appears to 

 characterize the " vestibule " in Delphinidse ; and, secondly, there 

 is no convex valve on the floor of the " upper chamber," as we 

 should expect if it were a " vestibule." 



But, however this may be, there is no uncertainty about the 

 lower one (B) : it communicates below \vith the naso-palatine 

 canal, while above it opens, by a canal, into the upper chamber : 

 it is a dilatation in the course of the narial canal. So that, which- 

 ever view is taken as to the upper chamber, it is clear that in 

 Oogia there are tw^o asymmetrically placed sacs, which though 

 physiologically, no doubt, corresponding with the series of paired 

 spiracular sacs in the Delphinidse, are morphologically different. 

 I have therefore avoided the use of the descriptive terms 



