Chap. XXVI. RELATIVE POSITION OF PARTS. 345 



faced races of the dog some of the molar teeth are placed in a 

 slightly different position from that which they occupy in other 

 dogs, especially in those having elongated muzzles ; and as 

 he remarks, any inherited change in the arrangement of the 

 teeth deserves notice, considering their classificatory import- 

 ance. This difference in position is due to the shortening of 

 certain facial bones, and the consequent want of space ; and 

 the shortening results from a peculiar and abnormal state of 

 the basal cartilages of the bones. 



Relative Position of Floivers with respect to the Axis, and of Seeds 

 in the Capsule, as inducing Variation. 



In the thirteenth chapter various peloric flowers were described, and 

 their production was shown to be due either to arrested development, or 

 to reversion to a primordial condition. Moquin-Tandon has remarked 

 that the flowers which stand on the summit of the main stem or of 

 a lateral branch are more liable to become peloric than those on the 

 sides ; M and he adduces, amongst other instances, that of Teucrium cam- 

 panulatum. In another Labiate plant grown by me, viz. the GaleoMolon 

 luteum, the peloric flowers were always produced on the summit of the 

 stem, where flowers are not usually borne. In Pelargonium, a single 

 flower in the truss is frequently peloric, and when this occurs I have 

 during several years invariably observed it to be the central flower. This 

 is of such frequent occurrence that one observer 15 gives the names of ten 

 varieties flowering at the same time, in every one of which the central 

 flower was peloric. Occasionally more than one flower in the truss is 

 peloric, and then of course the additional ones must be lateral. These flowers 

 are interesting as showing how the whole structure is correlated. In the 

 common Pelargonium the upper sepal is produced into a nectary which 

 coheres with the flower-peduncle ; the two upper petals differ a little in shape 

 from the three lower ones, and are marked with dark shades of colour ; the 

 stamens are graduated in length and upturned. In the peloric flowers, 

 the nectary aborts ; all the petals become alike both in shape and colour ; 

 the stamens are generally reduced in number and become straight, so that 

 the whole flower resembles that of the allied genus Erodium. The cor- 

 relation between these changes is well shown when one of the two upper 

 petals alone loses its dark mark, for in this case the nectary does not 

 entirely abort, but is usually much reduced in length. 16 



< Teratologie Yeg.,' p. 192. Dr. M. 2nd, 1861, p. 253. 

 Masters informs me that he doubts the M It would be worth trial to fertilise 



truth of this conclusion ; but the facts with the same pollen the central and 



to be given seems to be sufficient to es- lateral flowers of the pelargonium, and 



tablish it. f some ot k er highly cultivated plants, 



15 ' Journal of Horticulture,' July protecting them of course from insects : 



