38 Proceedings of the Royal Physical Society. 



Strand.^ They were also seen in both of the Shetland speci- 

 mens of Sowerby's whale, which I have described,2 and in my 

 summary of the external appearance of this animal I have 

 given " a pair of furrows converging in front on the under 

 surface of the throat " as one of the characters. They were 

 present, also, in the Ziphioid whale described by Burmeister 

 as Epiodon australe^ but which is probably the same as 

 Ziphius cavirostris. Hence their presence is a character to 

 be looked for in the sub-family of Ziphioid whales. But if 

 one may rely on the accuracy of Fig. 7 in PL XIX. of 

 Chamisso's Memoir, " Cetaceorum maris Kamtschatici," it 

 would appear that in the sperm whale (Physeter mcccro- 

 cephalus) a similar pair of converging furrows meeting in 

 front, as in Sowerby's ^hale, existed. Hence, one may 

 extend the generalisation, and state that in the whole family 

 of the Physeteridie a pair of converging furrows is present 

 on the ventral surface of the head. The presence of these 

 furrows is interesting as furnishing an approximation, in this 

 family of whales, to the much more extensive and well-known 

 fluted appearance of the belly, seen in the Eorquals or 

 Balasnopteridee. 



In Hyperoodon, Mesoplodon, and Ziphius, the pectoral limb 

 or flipper is small in relation to the size of the animal. In all 

 these genera the anterior border is slightly convex ; the pos- 

 terior border for several inches from the axilla is straight, then 

 makes a more or less sharp bend, and rapidly slopes forward, 

 so that the limb ends in a point. In the sperm whale the 

 pectoral limb is diminutive in relation to the size of the animal, 

 but its exact form has not been very definitely described. 



In Hyper oodon, Mesoplodon, and Ziphius, the dorsal fin is 

 situated some distance behind the middle of the back of the 

 animal. In the Dunbar male Hyperoodon the anterior border 

 of the dorsal fin was 2 feet 3 inches behind the middle of the 

 animal. In the sperm whale there is no definite dorsal fin, but 

 a hump on the animal's back some distance behind the middle. 



1 Oversight over d. K. D. Vidensk. Selsk., 1880 ; also Jouru. of Anat. and 

 Phys., April 1882, p. 459. 



^ Journal of Anat. and Pbys,, April 1882 and October 1885. 



^ An ales de Museo Publico de Buenos Aires, Eutrega quinta, torn i., 

 plate XV. 



