88 'M m-!» m iS to ^ K -7J m n ^ (\'i m % 



lie produced two ])Lint.s which ha\-c 13 and 21 petals as (heir sin<^Ie modes 

 respectively. This assiiniiitidii is confirmed by Ileincke (1898) from a study of 

 herrini; and by Jcnnin,L,^s (191 i) in the culture (jf Paramaecium. 



The statistic demonstration of the dimoqihic curve, which was carried 

 out by W'eldon (1894) on crabfish ( Carciiius inaenas), has (jeen verified by 

 GiL,'ard (1894) eniplo\-int,r the same material; he stales that the curve derived 

 from the small individuals is caused by parasites. 



Accordini: to Goldschmidt (19 1 3), who .stated on the win!:,^s of a moth, 

 Lyniantria iiio/mr/ia, the infeiior apex of the dimor])hic cur\'e comes from the 

 sniall t)-pe moulted always fi-om siiitII jnipae which in their tLU'n come from 

 poorly nourished citci-pillars. 



Besides de X'^ries, the three last named authors assume the dimorphic 

 curve to be caused In- einironmcntal factors. Bateson denies external circum- 

 stances which dri\'e the animal into the dimorphic condition, inasmuch as the 

 hiLjh and li iw forms are hMn;,;- close together under one and the same stone. 

 The results of the present in\-estigation are, therefore, in this respect in agree- 

 ment with those of Bateson. It follows that the dimorjjhic condition of a 

 species liviiiL^ under the same en\'ironmental circumstances is an inborn character. 



From the results of the present invcsti>_jation of Cladognathiis, the follow- 

 ing assertions are justified :- The female is less variable than the male. 

 Concerning the body IcugtJt. the latter is diniorpltic while the female is, on the 

 contrary, Kiiiiuodal. The tiiaudib'cs, or antlers of the male exhibit modifications 

 which ma_\- be said to be almost endless, until they are reduced to those of 

 the low types x'.hich arc nothing more than a pair of forceps; accordingly the 

 male in this respect, closely resembles the female which is provided wath 

 merel)' a pair of claw-like jaws. The resemblance goes not unfrequently so 

 far that a male and a female, which are about equal in body size, may not 

 at a glance be distinguished from each other when they are put into an insect 

 box, containin.n' man)' others. Thence, I dare to assume that the primary 

 form of the species was represented by the female, from which the male form 

 was derived b_\' the variation acting on it in producing the complicated ant- 

 lers from the claw-like mandibles. In fact the antlers are undergoing still 

 further modifications. 



