314 WHALES. 



velopes, the same relations as the dental capsule bears to the tooth. 

 According to these analogies, it must follow, that only the central 

 filjrous or tubular portion of the baleen-plate is formed, like the 

 dentine, by the basal pulp, and that the base of the plate is not 

 only fixed in its place by the cementing substance or capsule, but 

 must also receive an accession of horny material from it, as Hun- 

 ter first indicated ; this material answers to the cement of true 

 teeth. 



The baleen-plates are smallest at the two extremities of the 

 series : in the Balana australis they rapidly increase in length to 

 the thirtieth, then very gradually increase in length to about the 

 one hundred and fortieth, from this they as gradually diminish to 

 the one hundred and sixtieth, and thence rapidly slope away to 

 the same small size as that with which the series commenced. 

 Besides the external and, as they may be termed, the normal plates, 

 which have just been described, there are developed from the inner 

 part of the palatal gum, in BalcBua australis, a series of smaller 

 fringed processes progressively decreasing in size as they recede 

 from the large external plates ; the small plates clothe the middle 

 region of the palate with a finer kind of hair, against which the 

 surface of the tongue more immediately rests ; they are also arranged 

 in longitudinal series, which, however, are not parallel with the 

 external one, but pass from the inner margin of that series in 

 oblique lines inwards and backwards. The baleen-processes in each 

 of these oblique series gradually but progressively diminish in size 

 as the series tends backwards ; the shape of the base of the smaller 

 median baleen-teeth is rhomboidal or sub-circular; and, from the 

 parallelism of the oblique series, the pulps present the same quin- 

 cuncial arrangement as that of the feathers of birds ; we may say, 

 indeed, that such is the disposition of all these corneous productions 

 on the roof of the Whale's mouth, but that the pattern is obscured by 

 the disproportionate size and lamellar form of the external series of 

 plates. 



In the BalcEua mysticetus, the baleen-plates which succeed the 

 large ones of the outer row, are more numerous, and are relatively 

 longer and larger than in the Bal. australis : Mr. Scoresby, who in 



