684 JOURNAL, BOMBAY NATURAL HISTORY SOCIETY, Vol XI. 



canal, thus emphasing the general branched condition of the repro- 

 duced region of the tail. I have not previously observed either of the 

 above described peculiarities in single or bifid reproduced tails. 



By way of comparison with the above instances of caudal duplicity, 

 mention may be made of certain other cases of the condition which 

 have been recently examined by me. 



One of these is an instance of duplicity of another kind from those 

 already described. Its occurs in a specimen of Lacerta agilis. Gray 

 (Lacertidce), captured in the Botanic Garden, Cambridge. The forking 

 commences at 4*4 cm. from the cloaca and is in the vertical plane. 

 The dorsal branch is 1'5 cm. and the ventral branch 2'1 cm. long. Both 

 branches taper fairly regularly. The scaling throughout is that normal 

 to the species. The scales of the dorsal branch are however smaller than 

 those on the other portions. Serial sections show that the ventral 

 branch is the normal tail of the animal, while the dorsal branch is an 

 outgrowth from it, having the usual -structure of a reproduced tail. At 

 the forking the spinal cord runs dorsalwards from under the neural 

 arches of the immediately preceding vertebra, and after giving off a 

 branch of its central canal to the dorsal branch or supernumerary por- 

 tion of the tail, turns down again to pass under the neural arches of the 

 immediately succeeding vertebra. This condition is permitted by the 

 two vertebras concerned being unduly bent away from each other. In 

 fact, the tissues generally are much disturbed in this region, and sug- 

 gest that it has been the seat of an injury. The cartilage tube form- 

 ing the endo-skeleton of the supernumerary tail starts directly from 

 the neural arches of the more anterior of the above-mentioned verte- 

 brae, is at first incomplete ventrally, and becomes closed as it runs on 

 into the supernumerary tail. 



A case in its general features apparently similar to the above is 

 recorded by Giebel. * It occurred in the same species, but the 

 supernumerary (? reproduced) tail was borne on the ventral side of the 

 normal tail. 



A greater departure from the normal is exhibited by a Calotes 

 cristatellus, Fitz. [Agamidce) [Indo-Malayan region] in the Cambridge 

 University Museum. The dorsal surface of the abnormal portion of the 

 tail is shown in fig. 7. The first forking is 18*2 cm. and the second 



* Zeitshr. f, gesammt. NaturwisBenschaft, 1864. XXIV, p. 48. 



