BAL.EN01'TERA. 33 



1 foot 10 inches. The maxillary borders of the jaw 

 show a faint convex outline. See figure below. 

 Whale, nearly 50 feet long, stranded at the Old Bai-, 

 Aberdeen, 1889. Turner Collection. 



2. Tympanic bones, pair of broken, from the Aberdeen skull 



of B. muscukis, No. 1, Turner Collection. 



3. Tympanic bone, left, from B. musculus, 60 feet long, 



adult, stranded at Sandvoe, Northmaven, Shetland. 

 Length 5^ inches, breadth 3 inches; vertical height 

 3^ inches. Outer surface, more convex than in 

 sibhaldi, consists of a posterior larger and an anterior 

 smaller division separated by a short vertical groove ; 

 the distance from the groove to the posterior border is 

 3| inches, and to the anterior border 2J inches. The 

 lip-like pi-ocess ascends from the posterior division 

 and is bounded behind by a narrow groove. The 

 anterior border is differentiated into a ridge by a deep 

 groove immediately behind it. The inner surface is 

 more convex than in sibb<(hU ; the keel-like inferior 



3 



