S86 JOURNA L, BOMB A Y NA TUBAL HISTORY SOCIETY, Vol XL 



nearly across at the fiftieth vertebral articulation. On healing the 

 seat of injury was found to bear a structure resembling the terminal 

 seoment of the normal tail, and, like it, supporting a ten-rayed fin. 

 It is unfortunate that neither of the accounts of the last two quoted 

 cases mention what relation, if any, the new growths had with 

 the vertebral column. Superficially, however, the instances seem 

 to be of the same nature as those described in Lacerta and Ccdotes. 

 A tendency to hypertrophy on the part of tissues in process of 

 healing is of wide occurrence, and it may be that in the case of 

 certain structures which are capable of being reproduced as a whole, 

 e.g., the fin-rays in fishes and the tail in lizards, hypertrophic' 

 orowth consequent on a partial injury takes a relatively and pecu- 

 liarly constant form, simulating that which would have arisen in 

 the case of injury involving actual loss of the extremities of such 

 structures. But bearing in mind the number of different tissues 

 which compose so complex a structure as a tail and the complicated 

 ontogenetic development of the vertebral column, it is plain that 

 a final explanation of such appearances as are described above can- 

 not be offered at present. Experimental evidence on the subject is 

 greatly needed. If eventually it be fairly established that certain 

 kinds of injury involving the caudal vertebrae regularly result in 

 lateral growths of the same special nature as are known to arise 

 in the main axis after rupture of the tail, there will still remain the 

 question as to why these special structures, axial or lateral, should 

 occasionally exhibit duplicity on their own account. 



In connection with the above described cases may be mentioned an 

 abnormal growth of very defined form exhibited by a Lacerta muralis, 

 Latr., from Naples, in the Cambridge University Museum. As shown in 

 fig. 8, the dorsal surface of the left hind leg, immediately beyond the 

 knee-joint, bears a small tail-like structure. This is 1:1 cm. long, and 

 is covered by twelve or thirteen rings of scales closely resembling those 

 of the tail. It seems very probable that this is an hypertrophy arising 

 from the scar of an injuiry, for the dorsal surface of the leg has an 

 oval area of quite irregular scales, which are much larger than the 

 regular normal scales on the corresponding region of the other hind leg. 

 The normal pigmentation is partially absent on this oval area also, 

 and the general appearance suggests a healed wound. It is from this 



