Great Exhibition of 1851. 139 



The cetaceans, which afford the whalebone, or, more properly, 

 baleen plates, are of a more timid nature than the great sperm 

 whales, which commonly cause the catastrophes alluded to : they 

 have no teeth, but in their place they have substitutes, in the form 

 of horny plates, ending in a fringe of bristles, — a peculiarity first 

 pointed out by Aristotle.* Of these plates, properly called " ba- 

 leen," the largest, which are of an equilateral triangular form, are 

 arranged in a single longitudinal series on each side of the upper 

 jaw, situated pretty close to each other, depending vertically from 

 the jaw, with their flat surfaces looking backwards and forwards, 

 and their unattached margins outwards and inwards, the direction 

 of their interspaces being nearly transverse to the axis of the 

 skull. The smaller subsidiary plates are arranged in oblique series, 

 internal to the marginal ones. The base of each plate is hollow, 

 and is fixed upon a pulp developed from a vascular gum, which 

 is attached to a broad and shallow depression occupying the whole 

 of the palatal surface of the maxillary and of the anterior part 

 of the palatine bones. The base of each marginal plate is the 

 smallest of the three sides of the triangle ; it is unequally imbed- 

 ded in a compact subelastic substance, which is so much deeper 

 on the outer than on the inner side, as in the new-born whale to 

 include more than one-half of the outer margin of the baleen plate. 

 The form of the baleen-clad roof of the mouth is that of a trans- 

 verse arch or vault, against which the convex dorsum of the thick 

 and large tongue is applied when the mouth is closed. Each 

 plate sends off from its inner and oblique margin the fringe of 

 moderately stiff but flexible hairs which projects into the mouth. 

 The bases of the baleen plates do not stand far apart from one an- 

 other, but the anterior and posterior walls of the pulp fissure are 

 respectively confluent with the contiguous divisions of the bases 

 of the adjoining plates at their thin and extreme margins, which, 

 by this confluence, close the basal end of the interspace of the 

 baleen plates, which interspace is occupied more than half way 

 down the plate by the cementing substance or gum. Thin layers 

 of horn, in like manner, connect the contiguous plates, and may 

 be traced, extending in parallel curves with the basal connecting 

 layer, across the cementing substance. 



The baleen pulp is situated in a cavity at the base of the plate, like 

 the pulp of a tooth ; whilst the external cementing material main- 

 tains, both with respect to this pulp, and to the portion of the baleen 

 plate which it develops, the same relation as the dental capsule 



* The passage occurs in the 12th chapter of the 3d book of the " Historia 

 Animalium," and has given rise to much speculation and controversy : — "Mys- 

 ticetus etiam pilos in ore intus habet vice dentium suillis setis similes." To a 

 person looking into the mouth of a stranded whale, the concavity of the palate 

 would appear to be beset with coarse hair. The species of Balcenoptera, which 

 frequents the Mediterranean, might have afforded to the father of zoology the 

 subject of his comparison. 



