252 LILLJEBORG ON THE 



Pterobalæna mtjsculxjs, D. F. Enchricht. Undersogelser over Hvaldyrene, 6'*^ Afhand- 

 lings Kongl. Danske Vidensk. Selskabs Skrifter, 5'" Række, 

 1«^ bd., p. 87, 1849. 

 — COMMUNIS, P. J. van Beneden. Bulletin de l'Académie Royale des 



Sciences, etc., de Belgique, 2'"'= serie, t. 1, 1857, p. 403. 



Note. — The name " Rorhval" is derived from the Norwegian name " Ror-Qval," used by Strom^ for 

 a whale, which, from liis account, is probably the species now in question. Another whale, smaller, 

 but resembling this, is spoken of at the same place, as being in the habit of driving the spring 

 herring towards the coast, and therefore has been called " Sild-Qval," or Herring-whale, probably the 

 Balænoptera laticeps, or Rudolphi's Balæna rostrata, as it can hardly be the Bay-whale, or " Waage- 

 hvalen,'' which on the west coast of Norway is well known under the latter name, but is not called 

 " Sild-Qval." " The name " Rorqual " has since, by G. and F. Cuvier, been considered generic, which, 

 however, does not prevent its being applied to the species to which it originally belongs, and which 

 may be considered as the type of the genus. At first it did not appear to me probable that the rorqual, 

 the skeleton of which is preserved in the museum in Bergen, and the skull, &c. in the Zootomical 

 Museum in Christiania belonged to the same species as that from the Mediterranean, described by 

 Companyo, in consequence of the much greater length of body of the latter, although younger, and 

 some difference in the shape of the skull, atlas, and axis. The comparison below between the size of 

 certain parts of the skeletons of these rorquals has, however, very much removed these doubts, as it 

 thereby seems likely that the measurement of the length of the body stated by Companyo is not to be 

 relied upon, and that the same measurement given of the rorqual at Bergen is too small. Companyo 

 states the length of the body of the specimen described by him to be 25*60 mets., or 86' 8", and the 

 length of the skeleton 22-6 mets., or 76' 6i".^ The length of the rorqual caught at Bergen is, accord- 

 ing to Dr. Koren, said to have been 56' (Norwegian), or somewhat more than 58' (Swedish). As, with 

 the exception of the skull, the measurements of the various parts of the skeleton of Companyo's 

 rorqual, for instance the lower jaw, ribs, shoulder blade, upper arm-bone, and lower arm-bone, seem to 

 correspond with those of the latter, and not to denote any extraordinary size, it is reasonable to doubt 

 the correctness of the length of body stated by Companyo. It must be remarked, however, that the 

 measurements of a dorsal vertebra, given by Companyo, show a greater length of its body than on 

 the skeleton in Bergen. I presume that the length of the specimen in Bergen has been estimated too 

 low, from the fact that its skull and lower jaw very nearly correspond in their dimensions with the 

 skull and lower jaw in the Christiania Museum, and the specimen from which the latter were taken is, 

 accoi'ding to Lector Esmark, said to have been 68' (Norwegian), or nearly 71' (Swedish), in 

 length, which is more in correspondence with the usual length of older specimens of this species. 

 The measurements given of those colossal animals seem generally to have very little value 

 in comparing them, in consequence of the difficulty of taking the measurement in a straight line ; 

 more particularly when the body is much distended by gas. Besides, we find from measurements 

 given by Eschricht (loc. cit. No. 43), and those given by Van Beneden, that the older ones, even of 

 the same sex, are subject to considerable variations — more than 10' — in the length of the body. So 

 much for the difference of the measurements between Companyo's rorqual and the rorqual found 



^ Sondmor's ' Beskrivelse,' p. 298. 



^ The same opinion is expressed by Nilsson, in ' Skand. Fauna,' Daggdj., p. 637. 



^ The near correspondence in the length of the lower jaw makes it probable that Companyo's 

 measurement of the length of the skull is too great, and was taken along the upper arched margin of 

 the skull. 



