MORPHOLOaY OF THE PEDIPALPI. 



37 



(b) Limulus. — The masticatory function is retained tlirougliout. 

 Appendage ii. has six segments and is chelate. Appendages 

 iii.-vi. are always described as having six segments, but there is 

 distinct evidence of a fusion of segments 4 and 5. Appendages 

 iii.-v. are chelate, while vi. bears a number of spines at the 

 articulation between 6 and 7, and also at the end of 7. There is, 



Fig. 1. Pterygotus. Fig. 2. Limulus. Fig. 3. Scorpion. Fig. 4. Thelyphonus. 

 Fig. 5. Spider. Fig. 6. Galeodes. Fig. 7. Pseudoscorpion. 



further, a curious outgrowtli from the external side of segment 

 i., which seems to be of importance, as it is well developed at a 

 comparatively early stage*, but the morphological significance 



* Kingsley, Journ. Morph. vii. 



