CETACEA. 7 



merous separate narrow strips of whalebone, each ending in a 

 pencil of hairs, which vary in size from that of small twine to that 

 of tape, half an inch wide -, these are placed behind the others, 

 and gradually increase in size from the innermost to the broad 

 external series. 



The baleen or whalebone affords good characters for the sepa- 

 ration of this family into sections. 



Mr. Knox (Cat. Prep. Whale) gives the best account of the 

 development, position and distinction between the baleen of the 

 Whales of the North Sea which has come under my observation, 

 and it agrees with the observations I had made on the subject 

 before I could procure his pamphlet. 



In Balcena maximus, Knox (Physalus antiquorum), 314 ex- 

 ternal or labial plates (baleen) were counted on each side ; towards 

 each extremity these plates degenerate into bristles, and admit of 

 being counted with difficulty. Towards the mesial line the baleen 

 as a mass diminishes gradually in depth, giving the whole palatine 

 surface an elegant arched form. The 314 external or labial plates 

 do not extend to the whole extent in a transverse direction, but a 

 system of numerous small and narrow plates succeeds the exter- 

 nal ones. For each external plate, twelve (internal) smaller ones 

 could be easily counted ; so that the number of plates which could 

 be counted, and not including the bristly terminations towards 

 the snout, pharynx, and mesial line, stand thus : external or labial 

 plates, 314 ; internal small plates, corresponding to each external 

 one, 12 : total number of baleen plates, 3768. The longest plate 

 of baleen is placed about the centre of each of the sides, and 

 measured 26 inches in length and 15 in breadth. The substance 

 when recent is highly elastic and very heavy ; the whole weighed 

 nearly two tons. 



It is short or long according to the species of whale, being 

 modified entirely by the more or less arched form of the upper 

 jaw. Mr. F. Knox first pointed out this curious and important 

 fact. The usual conclusion come to by all persons was, that the 

 size of the whale corresponded to the length of the bone or ba- 

 leen. Now this is only good with regard to one species of whale, 

 and not at all to the whole group of Whalebone Whales. Knox, 

 Cat. Prep. Whale, 8. 



In Balana minimus, Knox (Bal&noptera rostrata), 307 external 

 or labial (baleen) plates can be counted on each side ; towards 

 each extremity these plates degenerate into fine bristles, which 

 were not counted. The plates hang perfectly parallel with each 

 other, and from their closeness and fringed lingual aspect, must 

 act as a very perfect filter in collecting the minute molluscous 

 animals, and at the same time enable the whale to eject the 

 water. The food of the Whale is still a much-disputed point. 



