178 



Mr Doncaste7% Note on an abnormal 



Note on an abnormal pair of appendages in Lithohius. By 

 L. DoNCASTER, M.A., Lecturer on Zoology, Birmingham University. 



[Beceived 15 March 1909.] 



In dissecting a specimen of the common English Centipede 

 {Lithohius forficatus), a student in the Birmingham Zoological 

 Laboratory found that it had an extra pair of appendages between 

 the poison-claws and the second maxillae. I did not see the 

 specimen before the appendages were removed, so cannot say 

 exactly how they were attached. The additional pair is repre- 

 sented in fig. 1, from a camera-drawing, and fig. 2 represents the 



Fig. 1. 



Fig. 2. 



poison-claws of the same specimen on the same scale. It will be 

 seen that the extra appendages are more nearly like poison-claws 

 than any other appendages of Lithohius, but differ in several 

 important details. They are much smaller, are differently jointed, 

 and instead of ending in one sharp tooth on which the poison-duct 

 opens, they have at their extremity a triple tooth in which no 

 duct is visible. It should be said that they had been soaked in 

 potash before they were carefully examined so that a rudimentary 

 poison gland and duct might have been present and destroyed. 

 Another point of interest concerns the median part of the 



