102 



Mr. E. R. Lankester. 



[June 15,. 



whether Dufour's account ought to he considered as erroneous, or as- 

 due to a difference in the species which he dissected. Whilst thus 

 doubtful I discovered that the Scorpio (Buthus of some authors) cyaneus- 

 of Ceylon presents a disposition of the ganglia of the ventral nerve-cord 

 and an innervation of the pulmonary sacs, which differs both from 

 that of A. funestus as described by Newport, and of A. occitanus, as- 

 described by Dufour. Further I have found that the Scorpio Italicus 

 (as also the allied Sc. Garpalhicus) has a disposition of these parts 

 agreeing with that observed by me in the Scorpio cyaneus of Ceylon. 

 Thus I am led to think it possible — though I cannot say that I think 

 it probable— that the difference in the accounts given by Newport and 

 Dufour of the two, species of Androctonus is due to specific variation. 



The disposition observed by Newport in his Androctonus, which I 

 can confirm so far as A. funestus is concerned,* is as follows : — 



Tracing the nerve- cord from the ganglionic mass in the cephalo- 

 thorax (or prosoma, as I prefer to call it), we find in the mesosoma 

 (the broad so-called abdomen of authors) a ganglion in the segment 

 containing the second pair of lungs, a second ganglion in the segment 

 containing the fourth pair of lungs, and a third ganglion in the lung- 

 less segment which succeeds the segment containing the fourth 

 pair of lungs. These three ganglia do not all supply the structures 

 adjacent to them : each sends off two lateral nerves and a median 

 inferior nerve. The latter nerve was not seen by Newport, but is 

 rightly described by Dufour. Dufour also observed what Newport 

 failed to do, viz., that the nerve-cord itself is double. The first and the 

 second pair of lungs, as well as the adjacent regions of the segments 

 in which they lie, are supplied by two pairs of nerves, which descend 

 from the ganglionic mass in the prosoma (cephalothorax). The 

 ganglion adjacent to the second pair of lungs supplies by its lateral 

 nerves, not that pair of lungs, but the third pair of lungs. The next 

 ganglion supplies the adjacent fourth pair of lungs, whilst the ganglion 

 in the segment following that containing the fourth pair of lungs 

 supplies the muscles adjacent to it, there being no lungs in this 

 segment. 



In the Ceylon scorpion, S. (Buthus) cyaneus, and in Sc. Italicus- 

 (Raes), I find, on the other hand, the following arrangement. There 

 are three ganglia in the broad abdomen, one placed very close to the 

 prosoma in the segment belonging to the first pair of lungs, a second 

 placed in the segment corresponding to the third pair of lungs, and a 

 third in the lungless segment. Further, the distribution of the lateral 

 nerves given off by the ganglia is quite different from what we find in 

 An droctonus funestus. 



In S. cyaneus of Ceylon only one (the first) pair of lung-sacs (and 



* June 24ifh. — Newport's drawing, however, represents the middle of the three- 

 ganglia as lying in the third lung-segment, instead of the fourth. 



