PEOFESSOE PLOWEE ON THE EECENT ZIPHIOID WHALES. 233 



sense middle forms, and that Berardius is, on the whole, the least modified or 

 specialized form, and approaches, therefore, nearer to the true Dolphins, while Hype- 

 roodon is the most specialized, being modified in the direction of the Physeterinae or 

 Sperm- Whales. 



The principal points stUl to be ascertained with reference to the skeleton of Berardius 

 are : — 1. Whether in the perfectly adult animal any further ankylosis of the cervical 

 vertebrae takes place. 2. What is the number of the phalanges of a perfectly com- 

 plete skeleton. 3. The form and size of the pelvic bones in the adult of both sexes. 

 4. Whether there is any difference in the development or form of the teeth in the two 

 sexes. 5. Whether there are any rudimentary, non-alveolar teeth concealed in the 

 gum of either the upper or the lower jaw. 



Any one who may be fortunate enough to see the animal in a recent state should 

 observe whether the cutaneous furrows on the throat, noticed in all other Ziphioids 

 hitherto examined, are present ; and it need scarcely be added that all observations on 

 the visceral anatomy as well as any facts bearing upon the geographical distribution or 

 habits of this rare and interesting Cetacean will be of great value in elucidating its 

 history and determining its true place in the natural system. 



DESCEIPTION OF THE PLATES. 



PLATE XXVII. 

 Fig. 1. Side view of the skeleton of Berardius arnouxi. 

 Fig. 2. The skull and vertebral column of the same, seen from above. 

 Fig. 3. The sternum, seen from below. 



All one sixteenth of the natural size. 



PLATE XXVIII. 

 Fig. 1. Side view of the cervical, dorsal, and two anterior lumbar vertebrae. The lines 



from the Roman numerals below the figure point to the surfaces for the 



attachment of the ribs. 

 Fig. 2. Anterior surface of the atlas. 

 Fig. 3. Anterior surface of the fourth cervical vertebra. 

 Fig. 4. Anterior surface of the fifth cervical vertebra. 

 Fig. 5. Anterior surface of the sixth cervical vertebra. 

 Fig. 6. Anterior surface of the seventh cervical vertebra. 

 Fig. 7. Vertical median section of the skull. 



Mx, maxilla ; PMx, praemaxilla ; Vo, vomer ; ME, mesethmoid, united with the frontal 

 above and the presphenoid below ; Na, nasal ; Fr, a number of loose wedge-shaped 



