MONSTERS IN ANIMALS. 247 



which was on the left side * : he was a married man, and had three fine 

 children. This one [scrotal] testicle became cancerous, and was ex- 

 tracted ; but the disease fell on the glands of the groin, of which cancer 

 he died. His son, afterwards Sir C. C, a lad of about eleven or twelve 

 years of age, died of a complaint in his lungs. I opened him, and 

 curiosity led me to examine the scrotum, and I found but one testicle 

 there ; it was of the right side : the other testicle was in the ring. 

 Was this similarity to the father accidental, or was it hereditary ? 



How far supernumerary parts are affected by the will. 



Supernumerary parts may be ■ so complete in their formation, as to 

 become in some degree a part of the whole as to use. If such super- 

 numerary part be endowed with powers of voluntary action, it is used 

 at the com m and of the will. I have seen a monkey which had two feet 

 on one leg (but which were rather two hands, each partaking much 

 more of the hand than a foot) 2 ; they, as it were, came out from one 

 tarsus, with a kind of division in the metatarsus ; but with only one 

 thumb, which was on the inner side of the inner hand. The tarsus 

 of course was broader than common. In the muscles on the leg which 

 move the foot and toes, there was a strange jumble. The ' tibialis 

 anticus ' appeared to make the ' extensor radialis ' of one of the hands, 

 and the •' peronasi ' made what could answer to the ' extensor ulnaris ' 

 which went into the outside of the other foot. The 'extensor pollicis' was 

 pretty regular, for a foot, as also the ' extensor digitorum communis ; ' 

 but, on the outside of these, between them and the two ' peronsei, 5 were 

 extensors to the outer foot, or hand, which were peculiar to it. The 

 ' gastrocnemius ' muscle, which rose as usual, was inserted into a bone 

 which might be reckoned either as ' os calcis ' or ' os pisiforme ' 3 , and 

 made either an extensor of the foot or a ' flexor ulnaris.' There was 

 nothing that answered to the ' flexor radialis ' of the fore-arm. 



As these were two pretty well-formed hands, had full and free motion, 

 and the animal made ready use of both, I found that the sciatic nerve 

 of this [left] side was larger than in the other [right side] in proportion 

 to their differences. This would make us suppose that it is not necessary 

 that the constitution of the brain should perfectly agree with the consti- 

 tution of the body ; the brain being calculated for a more compound 

 body than what it has ; because a new part, having the powers of 



1 [That is, he had one ' scrotal ' testicle, and the other ' inguinal,' or perhaps 

 abdominal.] 



2 [On the left leg : see the preparation, Hunterian Series of Monsters, No. 279, 

 < Catalogue of Monsters and Malformations,' 4to. p. 76.] 



3 [Perhaps the earliest recorded idea of this ' serial homology.'] 



