BALJiNOPTERA. 57 



61. Vagina, portion of, from the Loiigniddry .nhhaldi, to show 

 the transverse folds of the mucous coat. 



[Tendon, drawing of, from one of the great muscles of 

 the tail of B. sibbaldi. The tendon consisted of thick 

 fibrous laminae, arranged obliquely around a core 

 situated near one side of the tendon. Between the 

 laminse was a looser fibrous tissue, and in the 

 working of the muscle the laminae would seem to 

 move around the core as an axis, which would 

 impart a screw-like movement to the tail.] 



(3) Bal^:noptera p>orealis. (Bpt. r.) 



(Rudolphi's Rorqual.) 

 Balajnoptera borealis, Lesson, Hist. Nat. des Cetacees, 1828. 

 B. laticeps, Gray, Zool. Erebus and Terror, 1846. 

 Sejhval of the Norwegian Whalers. 



Colour bluish black on back, belly white with a shade 

 of yellow; length 38 to 45 feet, rarely 50 feet; 

 fourteen pairs of ribs, dorsal fin higli. Baleen mostly 

 black, but striped grey and white ; bristles white, very 

 fine to the touch. Outer border of superior maxilla 

 and premaxilla proceeding almost straight to tip. 



1. Skeleton, articulated, hyoid in position; first rib not 

 bicipital. Length of animal 38 feet, of skeleton 35 

 feet 2| inches, of skull 8 feet 1| inch; breadth of 

 skull 3 feet 10^ inches ; length of beak 5 feet 9 inches, 

 breadth at base 2 feet 6 inches ; mandible length 

 along outer convex surface 8 feet 8 inches. Vertebral 

 plates not ossified to bodies; formula C^Dj^L^^Cdoi = 56 ; 

 humerus 11 inches long, radius 20] inches, ulna 20| 

 inches. Length of shaft and manus 4 feet 7 1 inches. 

 From Kinneil, Bo'ness, Firth of Forth, September 

 1873. The first specimen to be recognised as a British 

 species. Described by Sir Wm. Turner, Proc. Buy. Soc. 

 Edin., vol. xi., 1882, and Journ. Anat. and Phys., 

 April 1882. See Plate VI. 



