CAUDAL ABNORMALITY IN LIZARDS. 685 



19'0 cm. from the cloaca. The three branches arise in the horizontal 

 plane, and from right to left are respectively 3*0, 2*3, and 4'7 cm. in 

 length. The soft parts form so thin a layer that the vertebral column 

 within can be easily traced without the undesirable destruction of the 

 specimen by section-cutting. The last vertebra present is bent out- 

 wards towards the right at an angle of 70°, so that the distal three- 

 quarters of its length run into and form the root of the right hand 

 branch. Beyond this point, which is "8 cm. from the inner angle of 

 the first forking, the right-hand branch is a reproduced structure. 

 So also are the whole of the other two branches and the short piece 

 from which they arise. This account is in agreement with the fact that 

 only on the right-hand branch, and on it only as far as the end of the 

 last vertebra, are the scales of the same size as on the normal region 

 of the tail. Everywhere else the scales, though of the normal type, 

 are smaller than on the region of the tail shown to be normal by the 

 presence of the vertebral column. 



The above instances seem to favour the often-expressed view that 

 caudal duplicity is at least sometimes brought about by a supernume- 

 rary tail growing out from an injured place, and the following case 

 described by Quelch* gives additional support thereto. A specimen 

 of Tupinambis nigropunctatus, Boulenger (Teiidce) y was placed in a 

 large cage in the museum of Demarara in company with alligators, 

 snakes, and other lizards. On its introduction its tail was in a normal 

 condition, but two years afterwards it was found to be bruised at 

 various points. There were doubts as to whether the injuries had 

 been inflicted by the alligators, by rats put into the cage for the 

 snakes, or by the striking of its tail against the wire-work sides of 

 the cao-e. It was however seen to fight with the rats. Soon after 

 the bruises were noticed, three supernumerary tails were observed to 

 be growing rapidly from three different points. At the end of another 

 year one of these was not much shorter than the normal tail, while 

 between the new growths three additional small stumps appeared 

 about to grow into supplementary tails. 



A somewhat similar observation among fishes has been recorded 

 by Malm.§ In a Pipe-fish (Syngnathus typhle) the tail was broken 



* Timehri {Jour. Roy. Agric. and Com. Soc. of British Guiana), 1890, IV, p, 118. 

 § Ann. des Sciences Naturelles (1^65). Se>: 4, XVIII (Zoologit), p. 056. 



