I've been training for a few months now..in my first few weeks of training..I made great gains in size of biceps and triceps..but lately I haven't noticed any different..

My biceps and triceps are getting more defined..yet they're the same size..anyone got any reccomendations for routines?

I work out one muscle everyday (Monday is chest&tris though)..and saturday sunday are off..

Tri Workout:
Dips: 2x8
Extensions: 4x10, 8, 8, 6
Dumbbell Skullcrushers: 3x10, 8, 6

Biceps:
Preacher Curls: 3x8
Hammer Curls: 3x8
Standing Barbell Curls (21ís): 2x21

I'm really trying to gain size..I've been eating like a monster..and am growing in every aspect except for bi's and tri's...especially biceps..

Help a brother out.