and n~ost wol.kc~~~s &I.(. I L ~ I . v ( ~ ( ~
t h t thv p r i n ~ ~ r y
s~cr(1tion from the cells
of I)ot,h Z O I I ( ~ S i11t0 th(, ~ n d ~ ~ t ~ l i t ~ '
g r ~ o v ( ~
is prutein and not mucus
((f. ( ~ ~ ~ ) ( * ( ~ i ; ~ I l y
I,(hvi i ~ , ~ ( l
I'oi~t,t~, I !Ni4 ; Olssoi~, I963 ; Ghiani et al., 1965 ;
CIo(t(~t~ux ;\II(I IQirl<(\t.. I !)(is ; 'I'l~orpc~ ( ~ t
( I / . , I !)72) hut Okson also produced
I
I*'lci. 8 . 'I'.S. o f ttsc-i~l~ttr~ o ~ ~ t l o ~ t y l ~ .
1 1 1 s111)w p o s ~ t i o ~ ~
~)l'rlifforol~t c1)1I zonns. For irlfwtifiont i o ~ ~
1 6 ~ t l i r n l ) ~ ~ r s
siSo tcbxl. (Ih.tlr.i~wn from Thorpt- ct ul., 1972.)
c.vidtwc.cx for solnc sc.cl.(ttion of muc~opolysnc.chttride and Ciodeaux and
I'it.lic~t (Ioc. (.it.) c.orisidi~t.ctl that zone 4 is the primary site of mucus
sc.c.~.clt io11 i l l t llc. (.nclostylc of Jlolgwln ~~rnahnften.uis (De Ka.).
%oilc. :3 is fit~c\l~c.ntly rrftlrrctl to as the vcntral ciliated zone but the*
\vo~*k of Gl1it111i i\11(1 Orsi (I$#fifi) a 1 ~ 1
Aros a11(1 \'irAgh (l!jfiCj) OII ion/^
i)t/ux/it~nlis i111tl (:odt.;~~rx ;trltl Firlt (I!)(i%) or1 il!r)lq~~1/1 manhn//rn.yis.