'224: C. F. GEORGE ON THE BLYBOROUGH TICK. 



He also states that Walckenaer describes one as nearly as possible 

 like that in question, under the name of Argas Fischerii. Un- 

 fortunately, I have at present no means of consulting that work. 



In Cuvier's " Arachnidae," published in 1833, with supplementary 

 additions by Griffiths and Pigeon, it states that Argas Perricus, 

 described by travellers, under the name of the venomous bug of 

 Miana, has been, as well as other Ixodes, the object of a curious 

 notice by M. Fischer, and also gives a drawing of Argas pipistrella, 

 somewhat resembling the Arachnid now under consideration, but 

 varying in important particulars. 



If it should prove that this Argas has not previously been de- 

 scribed, and is not Argas Fischerii, I should propose for it the name 

 of Argas pulchella, as it forms a very beautiful object for the lower 

 powers of the microscope, alive or dead — dry, or in balsam. 



It is almost circular in figure, having a slight projection anteriorly ; 

 it varies greatly in size, fine specimens measuring about three-twelfths 

 of an inch in diameter. The upper surface is somewhat convex, 

 and the edges slightly turn upwards ; it is much darker in colour 

 in the centre than at the edges, which are of a rich cinnamon. 

 Under the microscope, and by transmitted light, the abdomen is seen 

 to be filled with ceeca, elegantly arranged, and separated from each 

 other by circular cells, which, from their transparency, contrast 

 beautifully with the dark contents of the caeca. 



When the animal is alive, a sort of peristaltic motion may be 

 observed, occurring irregularly in various parts of the caeca ; the 

 action reminds one somewhat of the way in which the contractile 

 vesicles of the Infusoria disappear. 



The legs are eight in number, each terminated with a double claw, 

 at the base of which is a pad, and it is very curious to watch the 

 manner of using the claws and pad. If the creature is laid on its 

 back, and a piece of thin glass placed on it, with sufficient pressure 

 to prevent progression, but slight enough to allow it to make efforts 

 to walk, it will be seen that the claws are widely separated, and the 

 pad fits tightly on the glass, just as an india-rubber ball would do if 

 pressed upon, the pad then slips on the glass, and when the leg has 

 reached its limit of extension, the claws are suddenly brought to- 

 gether, forceps like, the pad in consequence becomes globular, and 

 is thus released from the glass. I have watched the process for a 

 considerable time, it is always repeated in the same fashion, and this 

 seems to me to explain the manner in which some insects, with pads 



