49 



broad, triangular, rather longer than broad at the base, and 

 edged with a series of elongate, unequal, bristle-like fibres, 

 which become nnich thicker and more rigid near the upper 

 tip. It is internally formed of one or two crowded layers 

 of thick tubular fibres, covered on each side with a thin 

 coat of enamel, which becomes thinner and thinner near 

 the edge, where the fibres are free ; it is always twisted, 

 and is only used to split into false bristles, but in this 

 they are inferior to the Southern or lowest kind of Baleen 

 of the Balanuc. 



These animals arc often called Razor-backs, by the 

 sailors. 



Balaenoptera sulcata Jacob, {Dublin Journ, Science, 

 1825, 333.) 



Dr. Jacob attempts to prove that Balmm Boops, B. ros- 

 trata, B. musculus, and B.jnbaries, are but one species; 

 and he has taken considerable trouble to bring together the 



measurements and proportions of the different specimens 

 which have been described. 



Hegives an outlineof his specimens, andcontrastsit" with 

 an outline of Hunter's Piked Whale, drawn according to 

 the measurements given by him;" and he observes, " that 

 the proportions of the body (of these two specimens) vary 

 in a remarkable manner, not only as to the situation of the 

 umbilicus and other parts, but in the breadth of the tail, 

 the length of the fin and arms. This, however, is what 

 should be expected, supposing Mr. Hunter's to have been 

 a j'oung animal, because such proportional superiority in 

 size of the extremities is characteristic of the earlier periods 

 of life." 



In the following table (observes Dr. Jacob), the first 

 column contains the dimensions of each part in feet and 

 inches ; the second, the proportion which each measure- 

 ment bears to the entire length of the animal, which is sup 

 posed to be 1,000. 



Professor Eschricht of Copenhagen, who has devoted 

 much time to the study of the anatomy and development 

 of the Northern species of this genus, and has published 

 several papers in the Danish language on the subject, in 

 'Transactions of the Danish Academy' for 1845-1846, has 

 kindly translated for me the following passage in his last 

 published paper, as the then result of his examinations : — 



" Of all that has been communicated in this chapter, it 

 appears to me to be proved, that amongst the Fin whales, 

 at least, three different species have their abode in the 

 Northern Seas : — 



I. In the Group of tite Longimana. 



1. The Greenland Keporkak. B. Boops, 0. Fab. B. 

 longimana, Rudolphi. 



II. In that of the Short-handed. 



2. The Norwegian Vaaga kval, B. minor ; and 



3. The common great short-handed, B. Boops. 

 To be almost proved that besides there exists, 



4thly. A peculiar large short-handed species. The Ba- 

 Icenopterus Musculus. 



And, at least, it is highly probable, that — 



Stilly. Tlie Greenlandian Kepokartrak is the represen- 

 tative of a particular form : and even that — 



6lhly. The Greenlandian Tikagalik or Balcena rostrata, 

 O. Fab., may be a different species from the Norwegian 

 " Vaagekval'."— Eschricht, Ath Mem. p. 157." 



M. Eschricht is now engaged in examining the speci- 

 mens of Balcenoptera, to be seen in the different Museums 

 of Northern Europe, to attempt to settle the synoniraa of 



o 



