ABSTRACT
I t is t r u e t h a t both b r a n c h e s o f the t r a d i t i o n t r a n s m i t the s a m e b a s i c r e p e r t o r y o f t h e m e s o r m e l o d y - t y p e s , a l t h o u g h o n e m u s t be c a r e f u l n o t to o v e r s i m p l i f y this p o i n t . T h e r e are c a s e s in which ag r o u p o f m e l o d i e s e m b o d y i n g as i n g l e u n i f o r m t y p e in o n e b r a n c h c o r r e s p o n d s to ag r o u p o f m e l o d i e s in the o t h e r b r a n c h t h a t is more d i v e r s e and may a c t u a l l y e m b o d y two o r m o r e d i s t i n c t s u b t y p e s . W h e t h e r such r e l a t i o n s h i p s are the r e s u l t o f d i v e r g e n c e in o n e b r a n c h o r m e r g e r in the o t h e r c a n n o t be a r g u e d h e r e . M o r e o v e r , s u c h o n e - t o - m a n y r e l a t i o n s h i p s , where t h e y o c c u r , c a n be construed as o n e - t o - o n e r e l a t i o n s h i p s in g e n e r a l c o m p a r a t i v e s t u d i e s w i t h o u t a f f e c t i n g the r e s u l t s . Ih a v e t h e r e f o r e a d o p t e d as aw o r k i n g a s s u m p t i o n the b r o a d l y a c c u r a t e v i e w t h a t e a c h m e l o d y - t y p e in e i t h e r b r a n c h c o r r e s p o n d s to one and o n l y o n e m e l o d y - t y p e in the c o l l a t e r a l branch. An e x a m p l e o f s u c h c o r r e s p o n d e n c e is s e e n in F i g u r e 1.
