306 LAWS OF VARIATION. Chap. XXIV. 



Arrests of Development : Rudimentary and Aborted Organs. 



Modifications of structure from arrested development, so great 

 or so serious as to deserve to be called monstrosities, are not in- 

 frequent with domesticated animals, but, as they differ much from 

 any normal structure, they require only a passing notice. Thus 

 the whole head may be represented by a soft nipple-like projec- 

 tion, and the limbs by mere papillae. These rudiments of limbs are 

 sometimes inherited, as has been observed in a dog. 81 



Many lesser anomalies appear to be due to arrested development. 

 What the cause of the arrest may be, we seldom know, except in 

 the case of direct injury to the embryo. That the cause does not 

 generally act at an extremely early embryonic period we may infer 

 from the affected organ seldom being wholly aborted, — a rudiment 

 being generally preserved. The external ears are represented by 

 mere vestiges in a Chinese breed of sheep ; and in another breed, 

 the tail is reduced " to a little button, suffocated in a manner, by 

 fat." s2 In tailless dogs and cats a stump is left. In certain breeds of 

 fowls the comb and wattles are reduced to rudiments ; in the Cochin- 

 China breed scarcely more than rudiments of spurs exist. With 

 polled Suffolk cattle, " rudiments of horns can often be felt at an 

 " early age ;" 33 and with species in a state of nature, the relatively 

 great development of rudimentary organs at an early period of 

 life is highly characteristic of such organs. With hornless breeds 

 of cattle and sheep, another and singular kind of rudiment has 

 been observed, namely, minute dangling horns attached to the skin 

 alone, and which are often shed and grow again. With hornless 

 goats, according to Desmarest/ 4 the bony protuberance which 

 properly supports the horn exists as a mere rudiment. 



With cultivated plants it is far from rare to find the petals, 

 stamens, and pistils represented by rudiments, like those observed 

 in natural species. So it is with the whole seed in many fruits ; 

 thus, near Astrakhan there is a grape with mere traces of seeds, " so 

 " small and lying so near the stalk that they are not perceived in 

 " eating the grape." M In certain varieties of the gourd, the tendrils, 

 according to Naudin, are represented by rudiments or by various 

 monstrous growths. In the broccoli and cauliflower the greater 

 number of the flowers are incapable of expansion, and include 

 rudimentary organs. In the Feather hyacinth (Muscari comosum) 

 in its natural state the upper and central flowers are brightly 

 coloured but rudimentary ; under cultivation the tendency to 



81 Isid.GeoffroySamt-Hilaire,'Hist. 34 ' Encyclop. Method.,' 1820, y>. 



Nat. des Anomalies,' 1836, torn. ii. 483 : see p. 500, on the Indian zebc 



pp.210, 223, 224, 395; 'Philosoph. casting its horns. Similar cases in 



Transact.,' 1775, p. 313. European cattle were given in in* 



92 Pallas, quoted by Youatt on third chapter. 

 Sheep, p. 25. 85 Pallas, ' Travels,' Eng. Translat. 



83 Youatt on Cattle, IS^-l, p. 174. vol. i. p. 243. 



