114 maljjnopterid.t:. 



II. Dorsal Jin hiyh, erect, compressed, falcate, ahout three-fourths the 



entire length from the nose. Pectoral Jin moderate, with 4 short 

 Jviigers of 4 or 6 phalanges. Vertehrce 55 or 04. Cervical rertebrre 

 not anchylosed. Neural canal oblong, transverse, Hibs 14 or 15. 

 Physalina, or Fiuner Whales. 



* Vertebrce 60 or 64. First rib single-headed. 



4. Benedenia. Rostrum of skull narrow, attenuated, vnth straight 



slanting' sides. Second cervical vertebra with two short truncated 

 lateral processes. First rib single-headed. 



5. Physalus. Rostrum of skull narrow, attenuated, with straight slant- 



ing sides. Second cervical vertebra with a broad lateral process with 

 a large perforation at the base. First rib single-headed. Sternum 

 trifoliate, with a long slender hinder process. 



6. CuviEHius. Rostnmi of sliuU broad, the outer side ciu'ved, especially 



in front. The second cervical vertebra with two short thick lateral 

 processes. First rib single-headed. Sternum oblong ovate, trans- 

 verse. 



** Vertebra 55. First rib double-headed. 



7. SiBBALDius. Second cer\ical vertebra with a broad lateral process 



perforated at the base. First and second ribs double-headed. Lower 

 jaw compressed, with distinct corouoid process. Vertebrse 55, 



III. Dorsal Jin high, erect, compressed, about two-thirds of the entire length 



from the nose. Pectoral moderate, with 4 shoHJingers. Vei-tebrce 50. 

 Cervical reiiebrce sometimes anchylosed. Neural canal broad, tri- 

 gonal. Ribs 11 . 11. Balsenopterina, or Beaked Whales. 



8. Bal^noptera. Second cervical with a broad lateral expansion per- 



forated at the base. First rib single-headed. Lower jaw with 

 conical coronoid process. 



The student must not run away with the idea that, because the 

 characters of the genera here given are taken from a few parts of the 

 skeleton, they are the only differences which exist between the skele- 

 tons of the different genera and species. The form of the head and 

 the peculiarities of the cervical vertebrae, of the ribs, and of the 

 blade-bone have been selected after a long and careful comparison of 

 the skeletons, as the parts which afford the most striking characters, 

 that can be most easily conveyed to the mind of the student in a few 

 words, and therefore best adapted for the distinction of the genera 

 and species. 



The careful examination of many skeletons has proved to me 

 that almost every bone of each genus is peculiar — that is to say, that 

 no bone is exactly alike in any two genera ; but the difference be- 

 tween them is often very slight, so slight that it would be almost im- 

 possible to convey an accurate conception of it to the reader by words 

 alone, yet it is permanent and characteristic. Though the same 

 bones of the different skeletons of the same species of Megaptera or 

 Physalus which I have examined offer a certain amount of variation 

 in minor particiJars, yet ahnost eveiy bone of each sjjccies has a 

 character of its own; so that a person conversant with the subject, 

 and fresh from the study and comparison, can say at once to which 



