180 



BALiENOPTERID.^, 



Length of skull in a straight lino 



Breadth of condyles 



Breadth of exoccipitals 



Breadth of squamosals (greatest breadth of skull) 



Length of supraoccipital 



Length of articular process of squamosal 



■Orbital process of frontal, length 



Orbital process of frontal, breadth at base 



Orbital process of frontal, breadth at outer end 



Nasals, length 



Nasals, breadth of the two, at posterior end 



Nasals, breadth of the two, at anterior end 



Length of beak, from middle of curved border of maxil- 

 lary to the tip of premaxillary 



Length of maxillary 



Projection of premaxillary beyond maxillary 



Greatest width of nasal aperture 



Breadth of maxillaries at posterior end 



Breadth of maxillaries across orbital processes (follow- 

 ing the curve) 



Breadth of beak at base (following the curve) 



Breadtli of beak at middle (following the curve) 



Breadth of maxillary at same point 



Breadth of premaxillary at same point 



Length of lower jaw in a straight line 



Height at coronoid process 



Height at middle 



Amount of curve (greatest distance of the inner surface ~| 

 of the jaw from a straight line drawn between the ex- I 

 tremities) J 



*' The atlas presents the characteristic features of this bone in other 

 members of the genus in a very marked degree. The transverse 

 process is particularly deep from above downwards, and much twisted. 

 The spinal canal is contracted in the middle ; the articiJar surfaces 

 for the axis are not confluent at their lower margins, but between 

 them is a distinct, oval, transversely elongated facet, and another 

 smaller round one is situated on the upper surface of a pointed 

 triangular projection from the hinder border of the inferior surface 

 of the bone, which runs under the body of the axis. There are thus 

 four distinct articular surfaces in connexion with the second vertebra. 

 The extreme width of the bone is 16|" ; the length of the inferior 

 surface of the body 4"-4, including the triangular process, which is 

 l"-5. The other dimensions are shown in the sketches (figs. 41 & 42). 



" The axis (fig. 43) has the usual form of this bone in the Fin- 

 Whales. The odontoid process is represented by a slight rounded 

 elevation, with a depression in the centre ; and besides the two large 

 lateral articular surfaces for the atlas, there are two small median 

 facets, one on the lower part of the anterior and one on the inferior 

 surface, corresponding to those above described in the first vertebra. 



