180 ANCEIM. 



there would be no trace of the anterior pair of legs). 

 In the young stages, this pair of appendages is long, 

 narrow, articulated, with a strong hook at the tip ; but 

 in the adult state they become more or less dilated and 

 shortened in form, varying in the different species. 



The character of the mouth does not appear to vary 

 until the animal has arrived at its adult stage. 



We have not yet observed, neither has M. Hesse shown, 

 the way in which, and the period when, the male assumes 

 the large, projecting mandibles. We assume it to be at 

 the last stage between the young animal and the adult, 

 and that these organs are produced at a single moult ; 

 though this is not in accordance with our experience of 

 the general development of this class of animals ; but, 

 certainly, the adult stage is one of a retrograde character, 

 a circumstance that may account for its departure from 

 the usual or normal plan. 



M. Hesse, in the 27th figure of his first plate, gives a 

 figure of a young animal in the act of moulting. He 

 describes it as a female, " represented at the moment 

 when it undergoes its transformation, and while it is yet 

 enclosed within the skin of Praniza that it is about to 

 quit." This, from our point of view, is merely the 

 development of a younger female into an older one. 



We have in our collection a very similar specimen ; 

 it is that of a male, but we cannot perceive in the 

 enclosed animal the large mandibles characteristic of 

 the male adult Anceus. We also possess small specimens 

 of the males, not more than two-thirds of the length 

 and half the breadth of the full-grown individuals of 

 this sex, and in which not only are the mandibles scarcely 

 more than one-fourth of the size of those of the latter,* 



* See woodcut in page 190 : d representing one of the mandibles of the 

 full-grown male, and d d that of the smaller individual. 



