52 Proceedings of the Royal Physical Society. 



(i.) Ehinal or prenasal arcs, 

 (ii.) Incisive or pre mandibular arcs, 

 (iii.) Mandibular arcs, 

 (iv.) Palatal or postmandibular arcs, 

 (v.) External pterygoid arcs, 

 (vi.) Internal pterygoid arcs, 

 (vii.) The velum or soft palate. 

 The hard palate, like the carapace of the Crustacea, is 

 formed by the union of ii., iii., and iv. hsemarcs. 



II. Mesothorax or pneumo-kista is formed by the ribs 

 meeting in the sternum or prokaulon, enclosing the hyo- 

 branchial splanchno-skelon. 



III. Metathorax, or aidoio-kista, supports the hypogastric 

 and pelvic viscera. 



Encircling these there are three limb zones or girdles, 

 each having a pair of members or limbs articulated to them. 



I. The temporal zone, formed by the squama-temporis — 

 zygoma and malar bone firmly binding the procranium and 

 metacranium over the mesocranium. In the glenoid cavity 

 the head of the maxilla or condyle is articulated, forming 

 the 1st laminar portion or pedicle ; 2d, the angle or tu- 

 bercle and base of the maxilla — lamella ; and, 3d, the 

 mentum or incisive portion or spine. 



II. The humeral zone or scapuloclavicular. 

 From the glenoid cavity. 



1st, The brachium or pedicle depends ; 



2d, The antibrachium or forearm ; 



3<#, The carpo-digital completes the lamina. 



III. The Coxal Zone or Pelvis. 



1. The femur is articulated in the acetabulum. 



2. The tibia and fibula form the lamella, but in this case 



the tarsus and toes may be viewed as a repetitive 



member. 

 (1.) The astragalus. 

 (2.) The calcaneum and navicular. 

 (3.) The toes. 



Perhaps the same arrangement should be adopted with 

 the carpo-digital. 



After these preliminaries we may proceed to the analysis 



