3 o 4 STUDIES IN THE EVOLUTION OF ANIMALS 



it may possibly have been a monstrosity which was not trans- 

 missible. 



All malformations connected with the extremities of the limbs 

 are hereditary and are easily transmitted from generation to 

 generation. This is a well-established fact, and proved by numer- 

 ous and well-authenticated examples. But M. Guinard and others 

 have shown that other anomalies, as long as the reproductive 

 organs are efficient, are also frequently inherited, such as hairiness 

 in man, hairlessness in other animals, hornlessness, want of eyeballs, 

 etc. If the anomalous individual cannot procreate, the anomaly 

 must die out with the individual possessor of it. 



Fishes lay an enormous number of ova. Supposing that some 

 external influence were adequate to modify the development of one 

 fish-embryo, it would be undeniable that a large number of ova 

 might be simultaneously and similarly modified. 



We have known an anomalous influence to pervade a whole 

 litter of puppies ; and the probability is that an anomaly of struc- 

 ture might occur in a whole litter of fishes, which might mean of 

 thousands \ Therefore we must begin to look upon monstrosities, 

 both now and in the past, suddenly appearing in a type, from what- 

 ever cause, as possible factors in the origin of species} 



1 In order to impress this important idea on the reader's attention, I will quote a 

 parallel case from the Vegetable Kingdom. Among market gardeners there is a Myosotis 

 (Forget-me-not) with almost every flower having many more petals than the typical 

 MyosotiS) which has only five petals. Most of the flowers have eight or nine petals, and 

 many have ten, which is exactly double the typical number. The sepals and stamens 

 correspond with the number of petals, so that there can be no doubt that the ten-petalled 

 flowers are fusions of two whole flowers, the fusion occurring while they are in their 

 embryonic stage. The oval centre of many such flowers plainly indicates a fusion of two. 

 It should be understood that in this form of Myosotis it is only the individual flowers 

 which are monstrous. I have ascertained that the ovules contained in the nucules round the 

 base of the conical style, are, many of them, fertilised, and Professor Henslow has it from 

 the grower, Mr. Appleton of Longford, that 80 per cent, of its seeds reprodttce this par- 

 ticular monstrosity, although insects must frequently cross-fertilise it with pollen of the 

 typical form, which now and again appears on this monstrous plant, and which also may 



