20 ME. M. lATJEIE ON THE 



On the Morphology of tlie Pedipalpi. 



By Malcolm LAtiEiE, B.Sc, E.L.S. 



[Eead 1st February, 1894.] 



(Plates III.-V.) 



I. Anatomy op TTielyphonus. 

 The internal anatomy of the Pedipalpi has, so far as my 

 knowledge of the literature goes, never been described in any 

 great detail * ; and though the following notes do not pretend to 

 touch on more than a few points, it seemed worth while to record 

 them, if only by way of calling attention to the need for further 

 inrestigation. That my material was limited in quantity and 

 badly preserved, is the only excuse I can offer for the incom- 

 pleteness of my observations, any attempts to trace the distri- 

 bution of the nerves or the details of the reproductive system 

 having been in vain. Sections through the whole animal were 

 tried with some small specimens ; but, apart from the difficulty 

 of cutting an animal so abundantly provided with chitin, the 

 inside was found to have lost all minute structure, and it was 

 almost impossible to discriminate between the various organs. 



Before entering on the subject of this paper, I wish to make a 

 protest against the indiscriminate way in which Arthropod 

 appendages are named. To^take an example : an appendage is 

 spoken of as " the third leg." I^ow this may mean (1) the third 

 appendage ; (2) the third postoral limb, i. e. appendage iv. ; 

 (3) the third walking-leg, which is in Scorpions appendage v., 

 and in forms like PTiryrius, in which appendage iii. is modified for 

 tactile purposes, it may be either appendage v. or appendage vi. 

 If one follows the same name through the Crustacea, the result is 

 even more bewildering. The use also of terms such as antennae, 

 mandibles, &c. is objectionable, as implying homologies with 

 other groups which are by no means certain ; and it would be a 

 great gain if writers would simply talk of the appendages by their 

 number. 



The hard parts of TJielyphonus are pretty well known, thanks 

 to the works of systematic zoologists ; but it will perhaps not be 

 out of place to give a brief description of the chief points, especially 

 as there are one or two new details to be noted. The sclerites of 

 the dorsal surface may be dismissed in a few words as consisting 



*' The only figures with which I am acquainted are those of Blanehard in 

 * L'Organisation du Eegne animal.' 



