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 scapulo-clavicular. 
From the glenoid cavity. 
Ist^ The brachium or pedicle depends ; 
2dy The antibrachium or forearm ; 
3c^, 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 cai'po-digital. 
After those preliminaries we may proceed to the analysis 
