SOUTHERN RIGHT WHALE 17s 



the side of the jaw, or on the mid-Une of the rostrum. This is further referred to in the 

 next section on the bonnet. 



BONNET 

 A characteristic feature of the Right whale is the presence on the snout of a large 

 callosity known to the old hand-harpoon whalers as the bonnet. This, and other 

 callosities, are plainly seen in the photographs (Plate XII, fig. i ; Plate XIII, fig. 2; 

 Plate XIV, fig. I ; Plate XV, fig. i). They are all nearly circular or oval in outline. The 

 bonnet is the largest and most anterior of the median dorsal callosities. A group of very 

 much smaller callosities occupies the mid-line of the rostrum between the bonnet and 

 the blow-hole, behind which lies a further small pair. On each side of the lower jaw 

 there is a further group of callosities. The most anterior is the largest, and it is roughly 

 kidney-shaped with a small circular callosity occupying the notch (Plate XII, fig. i ; 

 Plate XIV, fig. I ; Plate XV, fig. i). A line of small callosities runs back towards the 

 gape from this large anterior one. In whale No. 3560 the largest of the callosities was 

 I m. in diameter, this measurement referring apparently to the bonnet. On the mandible 

 the patches were smaller and nearly circular. They were fairly regularly spaced at 

 distances from one another of about 20 cm. Finally, there is a callosity on each side of 

 the head just above the eye. In size it is intermediate between that of the bonnet, the 

 anterior lower jaw callosities and the smaller ones on the rostrum and jaw. Lonneberg 

 (1906) illustrates the position of the callosities in this species. Callosities similar in 

 appearance and distribution are described from the Northern Right whale by Andrews 

 (1909). Ridewood (1901) examined a dried specimen of the bonnet of a Southern Right 

 whale, presented to the British Museum in 1864, and prepared microscopic sections 

 of it. He found it was composed of a mass of closely packed fibres set at right angles 

 to the surface of the skin. The bases of the fibres were hollow, for the accommodation 

 of vascular papillae. He points out the essential similarity of the structure to that of 

 the hoof of the horse, the horn of the rhinoceros and parts of the horns of oxen and 

 goats. This author well summarizes what was known of the bonnet, as follows : 



This wart or bonnet on the snout has been the object of many ingenious speculations. Gray 

 mentioned it as the opinion of a foreign zoologist, whose name is not disclosed, that the bonnet is 

 an excrescence formed by the adhesion of the barnacles called Coromila. A second opinion of the 

 same authority is that it is caused by the irritation of the whale-louse. Mr Holdsworth suggested that 

 it was a natural development, and was possibly characteristic of the species ; while Owen considered 

 it as due to disease of the outer layers of integument. Beddard, in his recent Book of Whales, states 

 that "it gives one the impression that it is a pathological structure, a kind of corn, perhaps produced 

 by the animal rubbing itself against rocks, as this species has been observed to do in order to get rid 

 of the barnacles which are apt to infest it. 



It is an interesting fact that the bonnet appears to be confined to the Southern Right whale. Gray 

 has expressed his inability to find mention of this structure in any account of the Greenland whale ; 

 and the experienced whaling captain, Mr Robert Kinnes of Dundee, writes, in a letter dated October 

 4th 1900, "that the Greenland whale has no excrescence on its nose". What is still further of interest 

 is the fact that in the whale figured by Gray in Diefltenbach's Travels in New Zealand, vol. n, as 

 Balaena antipodarum, there is a prominence on the front of the lower jaw as well as on the front of 

 the upper one. 



