494 Zoological Society: — 



form, proper to be considered a genus. Professor Lilljeborg ob- 

 serves, " Depuis peu vous considerez que mon B. robusta appartient 

 an genre Megaptera. D'apres les principes que vous avez suivis 

 dans la distinction des genres des Balcenopteres, cette espece, sans 

 doute, doit faire type d'un genre particulier." 



In tbe cervical vertebrae of all the genera of Finner Whales which 

 I have examined, and which have hitherto been described, the width 

 of the canal of the spinal marrow is rarely more than half the width 

 of the body of the vertebra : thus in Physalus the canal is 5| inches 

 wide, and the body of the vertebra 1 1 inches ; in Megaptera, which 

 had the largest and widest canal known until the discovery of this 

 Whale, the canal is 5 inches, and the body of the vertebra 9 inches 

 wide ; but in this Babbacombe Whale the canal is 6| inches, and the 

 body of the vertebra only 1\ inches wide. The cervical vertebrae of 

 the Balcenidce have a large canal for the spinal marrow, compared 

 with the size of the body of these vertebrae. 



The large size of this canal in Megaptera, Poescopia, and Cuvierius, 

 as well as peculiarities in other parts of the skeleton in the two 

 former genera, shows that the long-armed Humpbacked Whales 

 have some characters which make them, in some respects, more 

 allied to the Right Whales, or Balcenidce, than the other Finner 

 Whales. Eschrichtius is separated from both Megaptera and Poes- 

 copia by the regular and well- developed form of the lateral pro- 

 cesses, which are even larger and longer, compared with the size of 

 the body of the vertebra, than are found in any of the species of 

 Physalus or Benedenia. 



The canal of the spinal marrow in Eschrichtius is broader, com- 

 pared with the size of the body of the vertebrae, than it is in the last 

 cervical vertebra of Balcena biscayensis (the canal in this species 

 becomes wider, compared with its height, as it approaches the dorsal 

 vertebrae) ; for its width is only four-fifths of the width of the body 

 of the vertebra, while in Eschrichtius it is nine-tenths of the same 

 measurement. 



In the study of these animals, I have observed that the form and 

 proportion of the canal of the spinal marrow constitute one of the best 

 characters for the distinction of the Whales. Under these circum- 

 stances, I propose to form a genus for this Whale, under the name 



Eschrichtius. 



The external form and size of the pectoral fin, and the position 

 and form of the dorsal fin, unknown. Lower jaw with a very low, 

 strongly developed coronoid process. Vertebrae 60. Ribs 15 — 15. 

 The cervical vertebrae free, the body small, thick, suborbicular, qua- 

 drangular, rather wider than high ; lateral processes of the third to 

 the seventh vertebrae not forming a ring ; the canal of the spinal 

 marrow very broad, compared with the width of the body of the 

 vertebrae, and very high, subtrigonal, with rounded angles. The 

 second cervical not known. Bladebone with a distinct acromion and 

 coracoid process. Arm-bones broad, not longer than the humerus. 

 Fingers, phalanges half as long again as broad. The breastbone 



