SUBSTITUTION OF A WING FOR A LEG IN A MOTH. 69 



eggs that I have met with. It would seem from the few cases of 

 which I have any knowledge that the junction of the two 

 individuals composing the monster may take place in all kinds 

 of ways, and that a large portion of one, or both, may be dwarfed 

 or undeveloped, so that both individuals may be perfect, as in the 

 case of the Siamese twins, who were merely joined by a band 

 near the waist; both may be imperfect, as in the Two-headed 

 Nightingale, which was, I believe, double above the waist and 

 single below ; or one individual may be perfect and the other 

 represented by only a small portion of its body, as in the case of a 

 form which Professor Windle mentioned to me, and which is 

 happily very rare, of a perfect human being with a second head 

 placed upside down on top of the normal head, and also in the 

 case mentioned above of a hand or arm projecting from a sacral 

 tumour. Amongst quadrupeds I met with a case of a pig with a 

 second head projecting from the upper part of the true head. It 

 had 4 eyes and 4 ears, but only one body and 4 legs. It lived for 

 a few days ; but I did not hear of it until it was dead and buried 

 in a manure heap, and when its body came to be looked for it 

 could not be found, having been probably eaten by dogs or pigs 

 which were in the same yard, so that I was unfortunately unable 

 to secure the specimen. It was born at a publichouse in Chickerell 

 parish, within half-a-mile of my house, and was seen by many 

 persons whom I know. Professor Windle has not met with a similar 

 instance, but he tells me that the case of two heads side by side on 

 one body (diprosopus) is well known, also of one snout placed just 

 above the other, or normal snout, with only one eye, and that 

 placed in the middle at the front part of the junction of the two 

 snouts (Cyclopia). 



Now, the existence of the fifth wing in my specimen can be 

 explained, either by assuming that it forms the only developed part 

 of a second individual, the moth being the produce of a double 

 egg, which would be the case if we follow Professor Windle's law 

 for vertebrates, or we may put it in the same class as the five-winged 

 moths that I have mentioned, where the extra wing is implanted 



