1'J'J MKIUSTK VARIATION. [PART I. 



called ribs. ,,r some other equivocal character, but on the contrary 

 it el i" -id. -s changes in the number of prae-sacral segments 



that i- of large portions of the body, each with their proper 



-u|i|.l\ of nerves, vessels and the like, producing material change 

 in th.- mechanics and economy of the whole body: this moreover 

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

 -tenet- on the perfection and fitness of their bodily organiz- 

 ation. 



CARXIVOK.V. 



Th.- following cases, though few, have an interest as exemplifying 

 \.-rteliral Variation in another Order. 

 Id. Felis doraestica. In all the skeletons of FELIU.E that I have 



mined the formula is C 7, D 1 :i, L 7, S 3. A specimen of the 

 domestic Cat ha\in^ C 7, I> II, L7 is described by Struthers. The 

 chain:.- of aiticiilar processes from dorsal to lumbar was completed 

 between the l>th and L 9th vertebra but the posterior zygapophyses of 

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

 ..f .1 t ran-it ion joint. A- is -tat-d below, the change in the domestic 

 Cat iiormallv occur- h.-t \\i-i-n the 1 7th and 18th. I n this case therefore 

 \\ith increa-e in niiinlicrs of ribs the position of the articular change 



varied. Thi-. , , , d.-scrilied by STRl'THEKS, ./. Allot. /"*//?/,>(., 1S7-"), 



p. 'il, .V'- . hut the description there given differs in some respects 

 from that -tated alio\e. which i- taken from a letter kindly written 

 l>v l'rnfe--,ir Struthcr- in an-u.-r tn mv inquiries. 



There i- h.-re forward lloiinro-i-, in the development of ribs on the 

 _' 1 i vertebra, in the alteration iii position of the articular change, 

 and in the fad that the L'Sth i- not united to the sacrum. 



\ een in -..ni.- other cases, then-fore, with forward Homoeosis the 



numher of pne sacral \erteln-;e is increased ; hut as usual owing to the 

 ei|iii\ncal nature of caudal vertehr.-e it is not possible to state that 

 tin- total numher of \eitehra- is greater. 



Canis Vlllpes. N >rmall\. C 7, 1> !">. L 7: articular change from 

 dor .d to lnmhar het \\een 17th and l>th. 



1-7. Specimen ha \in-_' C 7, l> II, I. t'>. in which further the articular 

 chani.'.- occur- partly li.-t \\een the 17th and l>th. and partly between 

 the l^lh and I'.'th. In Mux. Coll. Sn^/. /,'.///;. Information as to 

 thi- -pecjnien \\a- kindly sent im-hy Professor STROTHERS. 



Jackal. Spi-.-iim-n h,i\in_; ('7. l> I .'!. L s instead nf 7. Articular 

 change as u-u.d h.-t ue.-n 17th and Isth. S'rufnir.iis /// //'//. 



(!!. Canis familiaris. Case of ,-.-r\ieal ril> mi left side borne by 7th 

 epical. This rili \\.i I in. |oi,.r and articulated with a tubercular 

 elevation on the 1 -t thoracic rih of the same side. The remaining 

 rili- and \ .-rt ehra- were normal. full\ described] CUTHKU, W., A ,-<!(. 



/. Anal. /'////>., . wits. .]/,,/.. IM',7. p. 'li'. Plate. 



[In connexion \\ it h t he foreifoin^ nli-,T\ at imis it mav he inent inm-d 

 that the arti-'idar chain.'.- does imt take place in the same place in all 



In t specimens of /'. /,,,, -j ,,f /: //'//;> and _' of /'. 1,,,,-tIn*, in 

 Edinburgh, and in one |.i,,n and one Ti-vr in Camhridge the lumbar 

 type he-in- 1,,'tueen the l>th and l!'tlia-in Struther's aluiormal Cat 



