32 JOURNAL, BOMBA Y NATURAL HISTORY SOCIETY, Vol. IX. 



In the present case the internal structure of the tail was examined 

 by means of serial transverse sections cut through the stump, and both 

 branches of the new growth, and longitudinal sections through the region 

 of the bifurcation. The features thus revealed are illustrated on Plate 

 B, figs. 3 to 6. It will be seen that the structure of the stump is that 

 of a normal tail, while each branch presents all the characters of a re- 

 newed tail as described by Fraisse. It is, therefore, unnecessary to give 

 a detailed account of the histology. The considerable degree of irre- 

 gularity of structure and the excentric positions of the cartilage tube 

 and of the central canal within it are more probably results of the dis- 

 turbing factor of the whole new growth being double than of its elabo- 

 ration under the changing circumstances of the active life of the 

 animal ; for it would appear from Fraisse's figures and from several 

 cases of renewed tails in other genera which I have examined that the 

 new growth is usually a symmetrical structure. It should be observed, 

 however, that in the present case there is a considerable degree of 

 asymmetry in the stump, a condition which, if it existed before the tail 

 was broken, may possibly have exercised some determining influence 

 on the form taken by the new growth ; though, on the other hand, it 

 is possible that the unusual nature of the latter brought about disturb- 

 ances in the nutrition of the stump. 



Many instances of caudal duplicity in lizards have been recorded, 

 and it has often been suggested that an explanation of this condition 

 is to be found in a second tail having grown out from an injured place. 

 It is quite possible that some cases have originated in this way, and in 

 the Cambridge University Museum there is an example of Trogonophis 

 wiegmanni (Amphisbcenidce) possessing what is apparently the stump of 

 a second tail growing out laterally near the tip of the normal tail. In 

 the present case, however, as shown in Fig. 6, the cartilage tube is 

 bifid from its commencement from the neural arches of the stump, 

 leaving no doubt that the whole of the new growth was elaborated at 

 one time. It is at present not possible to oifer an explanation of this 

 kind of duplicity, especially in the absence of experimental evidence. 



In conclusion a word may be said as to the difference between the 

 scaling of the two branches of the tail. It appears that, so far as the 

 epidermis is concerned, the median ventral line of the stump did not 

 divide with the tail, but continued along the long branch only, while 

 the short branch, though situated actually in the long axis of the 

 body, was treated as a lateral part and received the small scales normal 

 to the sides of a congenital tail. Strictly, therefore, the duplicity 

 has not involved the epidermis. A case which has possibly some 



