PSEUDORCA CRASSIDENS. 



211 



ments of one of the lumbar vertebræ in each of the species mentioned, will, perhaps, give 

 an adequate idea as to this point, better than a long description, and I have chosen for this 

 purpose to give the dimensions of the fifth lumbar vertebra, as one of those provided with the 

 highest spines : 



Total height 

 „ breadth 

 Height of the vertebral spine 

 Transverse process . 

 Length of the vertebral body 

 Breadth of the same 



In the speci- 

 men from 

 Refsnæs. 



In the speci- 

 men from 

 Middelfart. 



In a large 

 Orca glaaiator. 



In a very large 

 ca'ing-whale 



from the 

 Faroe Islands. 



8" 3'" 



9" 



15" 10"' 



13" 6"' 



11" 3'" 



12" 



17" 6"' 



14" 8"' 



4" 2'" 



5" Y" 



6" 9"' 



7" -.r 



4" 



4" T" 



5" 6"' 



5" 4"' 



3" 8'" 



4" 



5" 



4" 1"' 



3" %'" 



3" 



5" 9"' 



4" .-i"' 



In the anterior lumbar vertebræ the spines lean continually more and more backwards ; 

 but from the fifth the spines, as well as the arch itself, begin gradually to be placed in a some- 

 what more vertical position, without, however, proceeding so far that either the arch, or any of 

 the spines (not even farther backwards in the caudal vertebræ) are inclined in a forward 

 direction, and thus becoming, in this respect, directly opposed to the preceding ones, as is other- 

 wise generally the case, more especially in forms nearly related with ours. The peculiarity may 

 possibly, as far as the spines are concerned, be partly a consequence of their decreasing very 

 considerably in length ; but whatever its cause may be, it is very characteristic of our dolphin, 

 when compared with the allied forms, and it is only in the more distantly related beluga that 

 the anticline in the vertebral column has also as it were disappeared. The transverse process of 

 the first lumbar is inclined in a forward direction, contrary to the transverse processes of the 

 dorsal vertebræ, which point in rather a backward direction ; the angle, however, which this 

 process thus forms with the vertebral body has only a very slight deviation from a right one ; 

 this deviation, becomes still smaller in the nearest succeeding vertebræ, and the greater part 

 of the transverse processes of the lumbar vertebræ must be said to be placed at right angles 

 with their respective vertebræ. They preserve the same breadth throughout without becoming 

 broader towards their free extremities (as in certain other dolphins, for instance the narwhal), 

 the first of them may, indeed, be said to be the longest ; but there is only very Uttle difference in 

 this respect between this one and those nearest 'succeeding it. 



The foremost of the caudal vertebræ have bodies still thicker and as long as the hindmost 

 lumbar vertebræ, but from the fifth they become progressively shorter, and at the same time more 

 compressed, until finally the height of the bodies becomes greater than their breadth ; this shape 

 is then retained up to the place where the hæmapophyses disappear (between the fifteenth and 

 sixteenth caudal vertebræ) ; here, as usual in the dolphins, the appearance of the vertebræ is 



of the Delphinus griseus may be, can only be decided by an examination of the skeleton itself of the 

 last mentioned, preserved in the Paris Museum ; in his remarks upon the osteology of this species, 

 Cuvier mentions the vertebral column only very briefly, and does not give us any detailed description 

 of the vertebræ. A new and more accurate description of the skeleton of this remarkable form 

 vFOuld therefore remove an essential defect in Cetology. 



