300 THE WHALEBONE WHALES OF THE WESTERN NORTH ATLANTIC. 



between the navel and anus ; some entirely white spots ou the posterior ends of the 

 abdominal ridges. 



Pectorals gray on the upper surface except at the tip, usually with some 

 lighter blotches ; white ou the lower surface, anterior margin, and tip. Dorsal fin 

 dark gray, usually with whitish center crossed by light vertical, curvilinear markings. 

 Flukes gray above and below ; the lower surface with fine light and dark gray lines 

 running antero-posteriorly. 



Whalebone entirely black. 



Rostrum of the cranium very broad; free margin of maxillae convex; nasals 

 oblong, with truncated anterior margin. Vertebral formula: C. 7, D. 15 (-16), 

 L. 14 (-16), Ca. 26 (-28). Total, 63-65. 



BAL^ENOPTERA PHYSALUS (L.). 

 Common Finback. Plate 48, fig. 1. 



Form remarkably slender, size large. Head narrow and pointed. 



Average total length, 59 feet ; maximum, 81 or 84 feet (?). 



Pectorals, from head of humerus, 12 per cent, of the total length, lanceolate, 

 pointed. Dorsal fin moderate; its height about 2^ per cent, of the total length; 

 more or less falcate ; situated just posterior to line of anus. 



Color of the body dark gray above, white below ; the two colors merging by 

 imperceptible gradations on the flanks. Coloration of the head not bilaterally 

 symmetrical, there being more white on the right side than on the left, at least as 

 far back as the pectoral ; right ramus of the mandible white externally, and also 

 the anterior third, or more, of the whalebone; left ramus of the mandible and left 

 whalebone dark gray. Dorsal fin dark gray like the back. Pectorals gray on 

 dorsal surface, white on ventral surface and anterior margin. Flukes dark gray 

 above, white below, with gray posterior margin. Gray of the flanks extending 

 obliquely downward and backward from the pectorals toward the flukes, but not 

 reaching the inferior margin of the caudal peduncle, where there is a narrow white 

 edge, bounded anteriorly by a linear gray mark directed obliquely forward and 

 downward toward the anus. 



Whalebone gray striped longitudinally with yellowish white in varying pro- 

 portions ; anterior whalebone on right side of body all yellowish white. 



, Rostrum of the skull narrow and acuminate ; free margins of maxillae nearly 

 straight. Nasals narrow, and pointed anteriorly in the median line. Vertebral 

 formula: C. 7, D., 15 (-16), L. 14 (-15), Ca. 25 (-26). Total, 61-63. 



BAL^ENOPTERA BOREALIS Lesson. 

 Pollack whale. Plate 49, fig. 2. 



Form moderately robust. Size moderate. Average total length, 46 to 47 feet; 

 maximum, 54 feet. Pectorals, from axilla, 11 per cent, of total length, slender and 

 pointed. Dorsal large, high, and falcate ; vertical height about 4 per cent, of the 

 total length ; situated just anterior to the line of the anus. 



