" WIND-SCORPIONS. 341 



which the King-crab finds its place, appear also to have 

 originated by the adoption on the part of a Chaetopod Anne- 

 lid of a peculiar method of feeding. This consisted in 

 bending round the mouth with its large prostomium or 

 upper lip ventrally so that the limbs arranged along the 

 body could rake the food into the ventral middle line and 

 push it into the mouth. In process of time, various groups 

 of those limbs which were nearest the mouth became 

 specialised, some into jaws chewing the food within the 

 mouth aperture, others into sensory feelers (antennae).^ 

 There seems to me no possibility of connecting this 

 method of modifying the anterior segments, this ventral 

 bend of the first seoment of the Crustacea with the initial 

 specialisation of the ancestral Arachnid which as above 

 sketched involved a tilting upwards and backwards of the 

 first segment and the fusion of the upper and under lips to 

 form a rigid sucking beak. The two must be regarded as 

 separate and distinct modifications of their Annelidan ances- 

 tors. I repeat that, without such a qualitative analysis of the 

 segmentation as is here suggested, I do not see how the 

 question as to whether Limulus was an Arachnid or not, 

 a question that for more than a decade has divided zoolo- 

 gists into two almost hostile camps, could ever have been 

 finally settled, as I believe it now to be. 



The insects are another group of Arthropods with 

 which it has been thought the Arachnids might be asso- 

 ciated. Some remarkable resemblances occur here ag-ain as 

 in the cases of Scorpio and Limulus. The Insecta, like the 

 Spiders, typically have waists and ten segments behind the 

 waist. The number of segments in front of the waist does 

 not correspond, but it was thought that, if a pair of small 

 anterior antennae had disappeared from the Arachnids, then 

 the only difficulty would be removed. It is true that the 

 Arachnids had typically no trace of a '' head " marked off 

 by a " neck," but some approach to a head region could, it 

 was thought, be found in the helmet-like plate of Galeodes, 



^ The arguments on which this is based can be found in the author's 

 book on the Apodidte. Nature Series, 1892, and in two papers on the 

 Trilobites in the Q./oi/rn. Geol. Soc, vols, li., hi. 



