232 ' Talconer: Abnormal Spiders. ■ 



which now covers our valley floors, is in some measure at least 

 redistributed boulder clay, and this boulder clay in turn, is 

 in part the ice-borne sand and gravel of pre-glacial rivers. 



It is evident that more extended research will reveal the 

 presence of remains of the Glacial Period in these valleys to 

 a much greater extent than has formerly been supposed. 



In conclusion, I wish to record my indebtedness to Mr. 

 W. H. Sikes, who has taken much interest in the deposits, 

 and has also been at much pains to secure a large series of 

 photographs of the sections exposed, including those used in 

 illustrating this paper. Also to Prof P. F. Kendall and Mr. 

 A. Gilligan, for examining some of the sections, and with whom 

 I have had many helpful discussions on the problems involved. 

 I also desire to thank the directors of British Dyes, Ltd., and 

 Mr. Nicholson of the Huddersfield Brick and Tile Co., for so 

 freely granting facilities to visit their works. 



■: o :- 



ABNORMAL SPIDERS. 



WM. FALCONER, 



Slaithwaite, Huddersfield. 



Since writing on this subject,* I have been struck by the 

 frequency with which spiders have occurred to me with one 

 or both congeries of palpal organs imperfectly developed or 

 altogether . wanting. These organs,! appendages confined to 

 the male sex, are not of vital function, being employed only 

 in the act of generation, so that wanting them, those afflicted, 

 perforce having to remain bachelors, are of no account in the 

 propagation of the race. Otherwise they do not seem affected 

 in any other way, the individuals seen being well-grown and 

 coloured, active and vigorous. The cause of the defect is ob- 

 scure, but may have resulted congenitally from some eccen- 

 tricity in the protoplasm of the germ or from failure to complete 

 successfully an early moulting process in this part of its organism, 

 or other accident. As the palpal organs are only fully developed 

 and disclosed in the adult, they cannot be replaced by new 

 growths during a moult as is the case with lost limbs, so that 

 the condition is permanent. • 



Instances of mal-growth are, of course, from their very 

 nature, easily observable, while total loss in course of develop- 

 ment may be at once distinguished from that due to violence by 

 the smooth unbroken surface of the exposed ends of the palps, 

 much in the same way as the internal lacunae of water plants 



* Vide The Naturalist, May 1910, pp. 199-203, and June 1910, pp. 229-232. 

 f for figures of such organs see The Naturalist, Oct. 1912, PI. XV., figs. 

 1-7 and 21. 



Naturalist, 



