NOTES ON A SCIXK WITH AN ACCKSSOKY TAIL. l09 



the dorsal side, so thai here only three scales make up a whorl. For 

 the sake of comparison 1 have given in fig. 3 a sketch of that jjortiou 

 of the main tail which hegins with about the same thickness as the 

 accessory tail. It represents a ventral view of the main tail between 

 the points a and b on fig. 1, magnified to the same scale as fig. 2. At 

 this region of the main tail, there are, as in the hind portion of the 

 accessory tail, only three scales to a whorl, but with this prominent 

 difference, that here a stretch of fourteen ventral scales in a row takes 

 about twice as much length as the accessory tail, in which, as we have 

 already seen, there are the same number of corresponding scales. 



As indicated before, the main tail of the specimen in question is, for 

 its posterior greater part, a product of regeneration. This is fully 

 borne out not only by the nature of scales externally but also by a 

 certain point in the internal structuie. In the former respect the 

 accessory tail is essentially like the regenerated portion of the main tail 

 and I consider this as a sufticient evidence of its being also a product of 

 regeneration, formed by an excess, as it were, of that power. The two 

 tails are not inborn structure, as Bartels' ^ case seems to have been. I 

 find that in 1852 H. Miiiler- had explained in the same way as I do 

 mine, a case of double-tailed Lacerta tnridis that he investigated. In 

 that case, both tail-ends were evidently regenerated from the place of 

 one and the same cut of the original tail. So also the case of Ameiva 

 mentioned by Ryder. In the present case, however, the point of attach- 

 ment of the accessory tail and the point of regeneration of the main tail 

 do not exactly coincide, although the two lie in very close proximity to 

 each other. The origin of the accessory tail is a short distance in advance 

 of the regeneration-point of the main tail. 



1 IjiU'tels, M., Ueher ein lebeiiclos <ifabc]scliw;inziges Exen)i»lar von T.aci'rln ai/ili.f. 

 8it/Jjer. (Jes. Xat. Pr. Berlin. 1888. (I know this article only l>y »■ brief extract i^'iven 

 in Arcli. f. Xnturg. o'>. Jalir^. 2. Bd.) 



- Miiller, H,, Kine Eideclise, Lacerta riridis> init zwei filter einanier <4-elaj4'erten 

 Sclnviinzen, welche beide als das Product einer iiberreielien nnd diirch den feinen Ba.u 

 der wiedererzeugten, beuierkenswertlieu Eeprodiictionskraf't erschoiueu. Verliandl. d. 

 phy.-uicd. (jios. in Wiirzbnrg. Bd. II. 



