L'4 1 MKKISTIC VARIATION. [PARTI. 



It i-< noticeable that there is so far no case of an incisor appear- 

 in-- in tin- ii)i|n'i -jaw of Ruminants. 



'I'h,. evidence i- <li\i<k-d into two groups, the first relating t> 

 ine-i-.il-> ami raiiine>. tin- >.-e,m<l to preinolara and molars. 



Incisors and Canines. 



:it-">. Elephas africanus : the left tusk imperfectly doubled. The 

 n..,t <it' tin- ninth was douUe 1 , one root being outer and the other inner. 

 Tin- half i if the tusk arising from the outer root twisted round and over 

 tin- >i)i-r half so that at the other end it lay above and internal to it. 

 'I'll.- -tincture of the tusk was essentially double, but the two parts 

 \\i-re more or less hlcmled together in the middle third. The ex- 

 ternal ends vsere separate, ljut broken and somewhat deformed. 

 KI;IKI>I.O\\SKY, A., Sitzungsb. </. A'. Ak. Wien, 1868, LIX. i. p. 33.'?. 

 Plate. 



Horse. Supernumerary incisors common. MAGITOT, Anorn. tiyst. 



'//'/., p. 104, I'hiti'K. Numerous specimens in Museum of Veterinary 



School at Alfurt. 

 .'547. Specinifii having 12 upper incisors and 12 lower incisors belonging 



to the permanent dentition. GOUBAUX, Kec. med. vet., 1854, Ser. 4, I. p. 



71. Similar observation, LAFOSSE, Cours Hippiatrique, 1772, p. 32. 

 .S4s. Extra teeth of more or less irregular form placed behind upper 



incisors very common : many specimens in museum at Alfort. Speci- 



men ha\ing left '" as a double structure, the two halves not being 



-eparaled. (Alj'ort Max.) MAGITOT, /.('., PI. XIX. tig. 25. 



of incisor in Horse is rare. GOCBAUX, who has largely studied the subject, 

 knew no case of absence of any tooth in Horse, 1. c. 



349. Skeleton of ( art-mare in C. M. has only two incisors on the left side in the 

 ii]i|>iT ja\v. The teeth stand evenly and without break or trace of any other incisor 

 having been present. There is no sufficient indication to shew which of the incisors 

 is missing, lnit tlic two incisors present agree most nearly with i' 2 and j 3 . This 

 -p. run, n \\ii- first pointed out to me by Mr S. F. Harmer. (See also case given by 

 Kri'oi.rin, An<it.-]ilii/.t. Al/li., 1802, p. 14.").) 



*350. Marc of common breed, foaled March, 1876, having in the upper jaw no r in 

 either milk or permanent dentition, and in the lower jaw no permanent i' 3 . In the 

 upper jaw there were only 4 milk incisors, which were subsequently replaced by 

 I pcimanent incisors. Animal seen by MOROT in Apr. 1880; it then had 4 per- 

 manent incisor- in the upper jaw, but no i 3 . In the lower jaw permanent i 1 and i- 

 were in place, together with i 3 of the milk scries on each side. As Morot remarks it 

 is still possible that the other incisors might appear. Dam normal; half-sister 

 ahiininial, given in n, \t case. Mouor. Hull. Sue. mnl. vft., 1885, Ser. 7, n. p. 125. 



*.S5 1 . Mm" ""I of same mother as last case, by another sire, foaled Apr. 1877, had only 

 4 milk-incisor- in upper jaw. Seen by Morot at 3 years old, had then the teeth o'f 

 lower jaw animal, \i/. permanent ;', and milk /- and i 3 all in place. In upper jaw 

 \\ere permanent /' and milk /'-' on each side. The right milk /-'on the external side 

 bad a light groove jiarallel to the long axis of the tooth, suggesting that it might be a 

 double -tincture, but the groove \\its very slight and the crown was single. At five 

 years old this animal had the. normal (i lower incisors, but in the upper jaw left / :i 

 was absent. < *n the other hand a well-formed supernumerary tooth stood behind 

 right r 1 , right /-' being partly rotated. Ibid., p. 127. 



B also n curioii- case of " nine tusks " imperfectly described by CHAPMAN, J., 

 ill Interior <>/ S. Ai'rifii, n. p. '.is. 



