O CETACEA. 



Physeteridae, Gray, Ann. Phil. 1828 ; Selys Long champs, 1842. 



Cete hydrseoglossi B, Wagler, N. S. amp. 33, 1830. 



Cetaces, Lesson, N. Tab. Reg. Anim. 197, 1842. 



Cetacea, Rqfin. Anal. Nat. 60, 1815. 



Ruderer Wale, Oken, Lehrb. Nat. 661, 1815. 



Balenidia, Rqfinesq. Anal. Nat. 61, 1815. 



Balaenidae, Gray, Ann. Phil. 1828 ; Zool. Erebus and Terror, 15; 



Cat. Mam. EM. ; Selys Longchamps, 1842. 

 Vermivora, Lesson, N. Tab. Reg. Anim. 201. 

 Balcena, Lesson, N. Tab. Reg. Anim. 201. 

 Bale, Oken, Lehrb. Naturg. 663, 1815. 



The Baleen or Whalebone has generally been considered as the 

 teeth of the whale ; but this must be a mistake, for Mr. Knox 

 observes " In the foetal B. Mysticetus sixty to seventy dental 

 pulps were found on each side of each jaw, making the whole 

 number amount to from 260 to 300. The preparation (n. 56) 

 exhibits a portion of this gum with twelve pulps ; had these pulps 

 been confined to the upper jaw and corresponded to the number 

 of baleen plates, it would have formed a strong analogy between 

 the baleen and teeth ; but the number of baleen plates in the 

 whale greatly exceeds the number of dental pulps, and the lower 

 jaw, which contained an equal number of pulps with the upper, 

 has neither teeth nor baleen in the adult whale. Their presence 

 therefore in the fcetal Mysticetus forms one of the most beautiful 

 illustrations of the unity of organization in the animal ceconomy. 

 The teeth in the Balcena never cut the gum, but become gradually 

 reabsorbed into the system ; the very cavity in which the germs 

 were lodged disappear; whilst to suit the purposes of nature, 

 the integumentary system furnishes the baleen, which is evidently 

 a modified form of hair and cuticle." Knox, Cat. Whales, 22. 

 Professor Eschricht has shown also that the foetus ofMegaptera 

 Boops (Danish Trans. 1845, xi. t. 4) has numerous teeth on the 

 edge of the jaw, though they are never developed. I am inclined 

 to regard the baleen as a peculiar development of hair in the 

 palates of these animals, and somewhat analogous to the hair 

 found in the palates of the genus Lepus. 



From the examination I have been able to make of the baleen 

 of Balcenoptera rostrata, and of different masses of small blades 

 of Balcena australis, it would appear as if there was, at least in 

 those two species,, two series of baleen on each side of the palate ; 

 the external series being formed of large triangular blades placed 

 at a certain distance apart; and the internal, in Balcenoptera 

 rostrata, formed, of smaller, much thinner, triangular pieces^ placed 

 much closer together and forming a very dense screening appa- 

 ratus ; and in Balcena australis the inner series is formed of nu- 



