Plate 4. 



Fro. 1. (l())ii<)iicct(ii (isiaiiciis : ;il);ictinal asi»oct of type, p. 47. 



2. I'riiniash r a ikiIoiiiis : tip of ray. nctiual view, p. 50. 



3. I'ridiKistcr iH(<i<il(tt)ht.r : actiiial sui'facc of (ype, p. HG. 



551 



