122 MERISTIC VARIATION. [part i. 



called ribs, or some other equivocal character, but on the contrary 

 it effects besides changes in the number of pras-sacral segments, 

 that is to say, of large portions of the body, each with their proper 

 supply of nerves, vessels and the like, producing material change 

 in the mechanics and economy of the whole body : this moreover 

 in wild animals, struggling for their own lives, depending for their 

 existence on the perfection and fitness of their bodily organiz- 

 ation. 



Carnivora. 



The following cases, though few, have an interest as exemplifying 

 vertebral Variation in another Order. 



Felis domestica. In all the skeletons of Felidje that I have 

 examined the formula is C 7, D 13, L 7, S 3. A specimen of the 

 domestic Cat having C 7, D 14, L 7 is described by Struthers. The 

 change of articular processes from dorsal to lumbar was completed 

 between the 18th and 19th vertebra? but the posterior zygapophyses of 

 the 17 th, though of the dorsal type, have to some extent the characters 

 of a transition-joint. As is stated below, the change in the domestic 

 Cat normally occurs between the 17th and 18th. In this case therefore 

 with increase in numbers of ribs the position of the articular change 

 has varied. This case is described by Struthers, J. Anat. Phys., 1875, 

 p. 64, Note, but the description there given differs in some respects 

 from that stated above, which is taken from a letter kindly written 

 by Professor Struthers in answer to my inquiries. 



There is here forward Homceosis in the development of ribs on the 

 21st vertebra, in the alteration in position of the articular change, 

 and in the fact that the 28th is not united to the sacrum. 



As seen in some other cases, therefore, with forward Homceosis the 

 number of presacral vertebrae is increased ; but as usual owing to the 

 equivocal nature of caudal vertebra? it is not possible to state that 

 the total number of vertebra? is greater. 



Canis vulpes. Normally, C 7, D 13, L 7 ; articular change from 

 dorsal to lumbar between 17th and 18th. 



Specimen having C 7, D 14, L 6, in which further the articular 

 change occurs partly between the 17th and 18th. and partly between 

 the 18th and 19th. In Mus. Coll. Sure/. Edin. Information as to 

 this specimen was kindly sent me by Professor Struthers. 



Jackal. Specimen having C 7, D 13, L 8 instead of 7. Articular 

 change as usual between 17th and 18th. Struthers in litt. 



Canis familiaris. Case of cervical rib on left side borne by 7th 



cervical. This rib was lh in. long and articulated with a tubercular 



elevation on the 1st thoracic rib of the same side. The remaining 



ribs and vertebra? were normal, [fully described] Gruber, W., Arch. 



f. Anat. Phys., u. wiss. Med., 1867, p. 42, Plate. 



[In connexion with the foregoing observations it may be mentioned 

 that the articular change does not take place in the same place in all 

 Felida?. In 4 specimens of F. leo, 2 of F. tigris and 2 of F. pardus, in 

 Edinburgh, and in one Lion and one Tiger in Cambridge the lumbar 

 type begins between the 18th and 19th as in Struther's abnormal Cat 



