362 CETACEA. 



be procured. Since our acquisition of Alaska, the capture of this species 

 of whale has been carried on, while the older hunting-grounds, the Bays 

 of Monterey, Magdalena, and Balenas are neglected. 



The American Humpback, Mcgaptera Americana, is found in the 

 neighborhood of Bermuda, and attains a length of fifty to sixty feet. 



GENUS PHYSALUS. 



The general characteristics of this genus — which contains four 

 species — are as follows ; the head forms one-fourth of the total length, 

 the dorsal fin rises in the last quarter of the body, the pectoral fins close 

 behind the head ; the tail is deeply cut in the middle, forming two more 

 or less clearly divided flaps. 



THE RORQUAL. 



The Rorqual, Physalus antiquonnn (Plate XXVIII), is called also 

 the "Gibbar," the " Razorback," or the "Big Finner." It is the most 

 slender of all cetaceans, and the longest of all known animals, measuring 

 in some cases upwards of one hundred feet. The pectoral fins possess a 

 length of one-tenth of the creature's length, and a breadth of one-fifteenth. 

 The body attains its greatest thickness just behind the pectoral fins, but 

 towards the tail becomes so compressed that its vertical section is con- 

 siderably greater than its horizontal diameter. With the exception of a 

 few hairs, or rather of some horny filaments split at the extremity into 

 very fine threads, which are found on the upper jaw, the body is per- 

 fectly smooth, of a black color above, and pure white below. The deep 

 furrows which run from the lower jaw down to the navel, are of a 

 bluish-black. These furrows resemble cuts made with a knife. The 

 toothless jaws bear three hundred to three hundred and fifty plates of 

 baleen on each side, but this substance is short, coarse, and valueless for 

 ordinary manufacturing purposes. 



The Rorqual frequents the northern portions of the Atlantic Ocean 

 and the Arctic seas, and is especially abundant near Barendt's Island, 

 Nova Zembla, and Spitzbergen. When autumn begins, the Rorquals 

 migrate to southern waters, and are found during the winter in the seas 

 of the Temperate and Torrid Zones. 



