SCOTTISH HAIRWORMS 141 



Perthshire. The lack of northern records is probably due 

 simply to lack of material for examination, but this must be 

 left for the future to decide. Next in frequency comes 

 Gordius villoti, a designation which replaces a section of 

 the indeterminate Goi^dins aquatiais. It has been found 

 from the Tweed to the Moray Firth, and in some limited 

 areas appears in extraordinary abundance. No Scottish 

 specimen of Paracliordodes tolosanus, recorded from Berwick- 

 shire in 1853, has been seen by me, and the species is 

 therefore included on the authority of Dr Baird (1853). 

 P. pleskei has been captured only in a single locality in 

 Shetland. 



In the case of the Scottish species described below I 

 have taken the liberty of introducing English names, each 

 of which suggests a salient character of the form to which 

 it is attached. Except where other reference is given I am 

 responsible for the identifications. 



(i) The Faceted Hairworm (Figs. 3, 4, and 7). 



Parachordodes violaceus (Baird). 



( = Gordius violaceus.) 



A long brown worm, attaining in Scottish specimens a length of 

 7 to 12 inches, though continental forms up to 20 inches long have 

 been recorded. The colour varies considerably with the age of the 

 specimen, from almost honey-yellow in young individuals to a rich 

 dark brown in old examples, but the habitat seems also to have 

 some influence upon coloration. In each individual the colour is 

 uniform throughout, except that the tip of the somewhat pointed 

 head is white, succeeded by a dark band or collar with indefinite 

 margins surrounding the base of the head, and that in some 

 specimens the body bears along the back and the ventral surface 

 a dark central line more or less evident. There are, however, no 

 pale flecks scattered throughout the general body colour. 



Should the specimen be a male — and, fortunately, males are far 

 more numerous than females — preliminary microscopic examination 

 (magnification 50 diameters upwards) should be directed to the 

 forked tail (Fig. 7). The branches of the fork are stout and 

 cylindrical with blunt terminations, and they lie close together. 

 The cloacal opening lies in the central line of the body, opposite 

 the end of the slit which separates the two forks, and is surrounded 



