BALAZNIDsE 



241 



always, free, while in young individuals the axis vertebra may 

 likewise be separate. 



Neobalcema. 1 — Head about one-fourth the total length. Skin of 

 the throat not plicated. A small falcate dorsal fin. Vertebra?, 

 C 7, D 17, L 3, C 1G = 43 The cervical vertebra? are united. The 

 manus small, narrow, and tetradactylous, wanting the pollex. The 

 ribs remarkably expanded and flattened. The scapula very low 

 and broad, with completely developed acromion and coracoid pro- 

 cesses. Tympanic approximating to that of Balcena, but with certain 

 very characteristic peculiarities of shape. Baleen very long, slender, 

 elastic, and white. A single species, at present very rare, N. mar- 

 ginata, from the Australian and New Zealand seas is the smallest 

 of the Whalebone "Whales, being not more than 20 feet in length. 



Ehachianectes. 2 — This combines the small head, elongated form, 

 and narrow pectoral fin of Balcenoptera with the smooth skin of the 

 throat and absence of the dorsal fin of Balcena. The baleen is the 

 shortest and coarsest of any of the group. Its osteology is im- 

 perfectly known. One species, B. glaucus, the Gray Whale of the 

 North Pacific. 



Megaptera. 3 — Head of moderate size. Baleen plates short and 

 broad. Vertebra?, C 7, D 14, L 11, C 21=5 3. Cervical vertebra? 

 free. Scapula with acromion and coracoid process absent or rudi- 

 mentary. Skin of throat plicated. Dorsal fin low. Pectoral limb 

 tetradactylous, very long and narrow, attaining about one-fourth of 

 the length of the entire animal, the metacarpus and phalanges 

 being greatly developed, and the latter very numerous. Tympanic 

 still more inflated than in Balcenoptera, with the involuted portion 

 more distinctly pyriform, the Eustachian part of the aperture well 

 defined, and two well-marked longitudinal ridges on the lower 

 surface of adult specimens. 



The Whale commonly called " Humpback " (Megaptera hoops) by 

 whalers, perhaps on account of the low hump- like form of the 

 dorsal fin, is very distinctly characterised from all others of the 

 group, especially by the immense length of the pectoral fins or 

 flippers, which are indented or scalloped along their margins, and 

 are, except at their base, of a white colour, nearly all the rest of 

 the body being black. The baleen plates are of a deep black 

 colour. Though common in the North Atlantic between Norway 

 and Greenland, this Whale does not frequently appear on the coasts 

 of the British Isles. One came ashore at Newcastle in 1839 ; 

 another, a young one, was taken in the estuary of the Dee in 1863, 

 and its skeleton is preserved in the Liverpool museum ; and a 

 nearly full-grown animal was captured in the mouth of the Tay in 



1 Gray, Sujypl. Cat. Seals and Whales in Brit. Mus. p. 39 (1871). 



2 Cope, Proc. Ac. Nat. Sci. Philad. 1869, p. 15. 



3 Gray, Zoology of Erebus and Terror, p. 16 (1846). 



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