NOTES ON A SCINK WrTH AN ACCESSORY TAIL. 118 



not succeeded in tracing these nerves proximal]}^ but there can be no 

 donbt of their spinal nature. W'ithin the accessory tail, they traverse 

 down the axial areolar tissue, splitting into finer branches (fig. 10). 

 Besides giving off these nerves, the spinal cord itself has nothing to do 

 with the accessory tail. This also holds good for the caudal artery and 

 vein, and likewise for the axial skeleton. Inferring from cases hitherto 

 described of double-tailed lizards, e.g. such as those of H. Miiller, ^ 

 Simroth - and Piana '^ I had anticipated to find in the accessory tail a 

 branch or at least some sort of a continuation of the axial skeleton ; but 

 in this I was mistaken. The accessory tail has no interval skeleton at 

 all. In the absence of all such central organs, one might question with 

 certain justification the propriety of designating the superfluous ap- 

 pendage in question as a tail at all. 



There remains yet an abnormality, which I find in the caudal 

 vertebra to be mentioned with special emphasis. It concerns a vertebra 

 immedial}'^ preceding the half vertebra already mentioned and situated 

 just opposite the origin of the accessory tail. The anterior and the 

 posterior portions of the said vertel)ra are of quite usual shape and 

 structure, but the middle portion shows a considerable disturl)ance from 

 the normal state (fig. 4). This consists especially in the very irregular 

 shape of the medullated vertebral body and of a portion of the neural 

 arch on the right side, both of which send out some excrescences 

 f)f indefinite form. There also exists on the right of the vertebral body 

 a gap or two, which brings the pia mater of the spinal cord in direct 

 coimection with the perivertebral areolar tissue and which seems to 

 have dislocated to a certain extent the neural arch on the same side. 

 As a consequence of this disturbance the vertebral canal is considerably 



1 Loc. cit. 



- Simroth, H., Uber einige Doppelbildnncfen sonst einiaclier Organe bei Tieren. Zeifr. 

 f. d. ges. Xaturw. von Giebel. Bd. 52. 1879. (I know this article only by a brief extract 

 given in Zool. Jahresb. f. 1879.) 



3 Piana, d. B., Kecerehe siiUa polidactilia acquisita deteri)iinata sperinientaluiente 

 nei Tritoni et snlle code soprannmerarie nelle Lacertole. Kio. Tjnbor. Anat. norm. Ifoma. 

 Vol. 4. 1891'. (T know this article only by a brief extract given in Zool. Anz. 17- -bihrg. 

 Nv. 450.) 



