552 



CETACEA. 



slender for a Balcsnoptera, being even more so than in Bal(sna mysticetus as viewed 

 laterally {vide Oss. Foss., PL XXVI, fig. 9), whUe the coronoid process is weU 

 developed, as in Gray's figure of the lower jaw of Balcsnoptera rostrata ( Zool. 

 Voy. Erebus and Terror, Cetacea, p. 22 ) ; the base of the jaw, however, posterior to 

 the process is not deeper, as in that figure, but the reverse, and the jaw is proportionally 

 much longer anterior to the process. The entire length of each ramus is within 

 less than two inches of twenty-one feet, showing the head to have been about one- 

 fourth of the total length. Vertical diameter three feet ; in advance of summit of 

 coronoid eighteen inches (measured by calipers) ; at three feet from tip, 13-50 inches ; 

 and where most contracted, posterior to the coronoid, fifteen inches only ; extreme 

 depth at coronoid process (inclusively) 26-75 inches. Erom middle of coronoid to 

 summit of condyle posteriorly in a straight line, 37-50 inches. The shaft of the 

 ramus is more approximately of the same thickness thi'oughout than in Balcena 

 mysticetus, tapering quite evenly." Professor Elower ^ has observed on these remarks 

 by Blyth, that his description of the coronoid process of the lower jaw indicates 

 that it did not belong to the genus Sibbaldius, but was probably a Fhysalus. The 

 jaw, however, does not differ structm-ally from the jaw of the Whale found near the 

 Sittang, and which I propose to designate B. edeni. It, moreover, agrees with 

 Elower's description of the jaw of Balcsnoptera: " Rami of lower jaw much curved 

 and with a high pointed coronoid process. " The radius is 35-60 inches long, and 

 Blyth remarks it is " nearly similar in shape to, but more curved than, that of 

 Megaptera poeslcop (Rorqual du Cap, Ouvier, Oss. Eoss., PL 227, fig. 22 e). The 

 shape of this bone in Balcena, as figured by Cuvier, is remarkably different." 



The rib is proportionally small, measuring only 8 feet 2 inches round its curva- 

 ture to superior articulation. It is probably the third of the series on the right side. 



The five vertebrse which Blyth originally considered as belonging to two dis- 

 tinct Whales he afterwards, I believe, correctly regarded as having belonged to the 

 same individual. Two are dorsal, according to Blyth, but they are undoubtedly 

 the first and second lumbar vertebrse, if the animal had only ten ribs ; however 

 they have been much hacked and are mutilated of their processes. I differ also 

 from him regarding the positions he assigned to the others. 



Proc. Zool. See, 1864 p. 408, footnote. 



