26 



SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



An alteration in the attachment of the ventral muscles similar to 

 that which evidently has taken place in insects may be observed also 

 in the Chilopoda, here between members of different families. In the 

 Geophilidae and in Lithobius the ventral longitudinal muscles consist 

 principally of two flat, widely-separated bands of fibers lying close 

 against the body wall and inserted on intersegmental sclerotizations. 



Fig. 17. — Ventral view of the base of the prothorax, the mesothorax, the 

 metathorax, and the base of the abdomen of the large South American embiid, 

 Cylindrachaeta spegazzinii. 



d, ventral articulation of coxa w^ith subcoxal laterosternite {Ls) ; k, f ureal 

 suture ; /, secondary suture of mesosternum ; Ls, laterosternite ; iSi, anterior 

 plate of mesosternum; 2Si, posterior plate of mesosternum (furcasternite) ; 

 Ti, ventral fold of protergum. 



In Scolopendra and Scutigcra, on the other hand, both the longitudinal 

 ventral muscles and many other muscles of each segment are attached 

 on two ligamentous supports that arise from the posterior parts of the 

 segmental sternites. In Scolopendra each ligament has a separate 

 origin on the sternum ; in Scutigcra the two ligaments in each segment 

 arise from a common base, forming thus a furca-like structure 

 (fig. 10 B, Fu) suggesting that of the higher pterygote insects. 



It is scarcely possible that there is any genetic relation between the 

 f ureal apophyses of insects and the muscle-supporting structures of 



