Likewise the role of the c~ot~xul striintl in rrlation to thc visceral fibre
complex retniiins to b t b cl\i(.itlittt.tl. ‘l’h(w is doubt also about, the nature
of synaptic t~.ii~lsr~~itt~.r,ci i i i awitliiw nrrvc~s and the function of the
secretory cclls in the giinglion.
Thv function of the ileurid gliLt1tl rt3rnairis i ~ i i
enigma. I t is dear that
it is eiigagetl in cyclioul activity resulting in thc sloughing of cclls into
the interior lunicn of the glibnd but differences of opinion still exist as
to the fate of these cells, and whether or not they are discharged through
the ciliated funnel. If discharged they are likely to become wrapped up
in the food cord forming on the dorsal lamina. In spite of many attempts
to homologize the neural &id with the vertebrate pituitary it seems
that an,y hormonal activity in the gland is at a level comparable to that
found in other tissues of the unimiil and the cvidence suggests that it is
not, a specialized endocrine organ.
XV. ACKNOWLHUOEMENTS
Much of this review was prepared at the Plymouth Laboratory of
the Marine Biological Association during a sabbatical leave. I am
particularly grateful to the University of the West Indies and to the
Nuffield Foundation for the finuncial assistance which made this possible ; also to the Director o f the Plytnouth Laboratory for providing
me with fiiclilities. Many othcr pcople huve helped in various ways and
particular thanks are due to the Library staff at Plymouth for their
constant assistance, to I)r Eve Southward for help with the literature
after my return to JarnairiL and to Mrs Elaine Fisher for preparing
many of the illustrations. I also wish to thank Dr George Mackie and
his colleagucs and I)r John Croxull for perniitting me to read and to
quote from their unpublished niunuscripts.
Acknowlt~dgeme~it~ is also made to the following publishers for
permission to reproduce original matsriul as indicated : The Wistar
Institute I’rchss (Fig. 5 ) ; Springer Verlag, New York (Pig. 6 ) ; The
Marine Biological Laboratory, Woods Hole (Fig. 7) ; Universitb di
Genovit (Fig. 9) ; Masson et Cie, Paris (Fig. 1 0 ) ; Oliver and Boyd Ltd.,
Edinburgh (Fig. 13) ; The Rockefeller University Press (Fig. 14) ;
Microforms International Marketing Corporation, Tnc. (Big. 28) ; Itugnur
Olsson, Stockholm (Fig. 30).
I thank iilso the authors of t,hese illustrations who liavc givtbn
pcmiiasion for their rcyrodiic4ioi1 i i n t l whose iiiimrs uplwnr in the
relevcult ( y t ioiis.
complex retniiins to b t b cl\i(.itlittt.tl. ‘l’h(w is doubt also about, the nature
of synaptic t~.ii~lsr~~itt~.r,ci i i i awitliiw nrrvc~s and the function of the
secretory cclls in the giinglion.
Thv function of the ileurid gliLt1tl rt3rnairis i ~ i i
enigma. I t is dear that
it is eiigagetl in cyclioul activity resulting in thc sloughing of cclls into
the interior lunicn of the glibnd but differences of opinion still exist as
to the fate of these cells, and whether or not they are discharged through
the ciliated funnel. If discharged they are likely to become wrapped up
in the food cord forming on the dorsal lamina. In spite of many attempts
to homologize the neural &id with the vertebrate pituitary it seems
that an,y hormonal activity in the gland is at a level comparable to that
found in other tissues of the unimiil and the cvidence suggests that it is
not, a specialized endocrine organ.
XV. ACKNOWLHUOEMENTS
Much of this review was prepared at the Plymouth Laboratory of
the Marine Biological Association during a sabbatical leave. I am
particularly grateful to the University of the West Indies and to the
Nuffield Foundation for the finuncial assistance which made this possible ; also to the Director o f the Plytnouth Laboratory for providing
me with fiiclilities. Many othcr pcople huve helped in various ways and
particular thanks are due to the Library staff at Plymouth for their
constant assistance, to I)r Eve Southward for help with the literature
after my return to JarnairiL and to Mrs Elaine Fisher for preparing
many of the illustrations. I also wish to thank Dr George Mackie and
his colleagucs and I)r John Croxull for perniitting me to read and to
quote from their unpublished niunuscripts.
Acknowlt~dgeme~it~ is also made to the following publishers for
permission to reproduce original matsriul as indicated : The Wistar
Institute I’rchss (Fig. 5 ) ; Springer Verlag, New York (Pig. 6 ) ; The
Marine Biological Laboratory, Woods Hole (Fig. 7) ; Universitb di
Genovit (Fig. 9) ; Masson et Cie, Paris (Fig. 1 0 ) ; Oliver and Boyd Ltd.,
Edinburgh (Fig. 13) ; The Rockefeller University Press (Fig. 14) ;
Microforms International Marketing Corporation, Tnc. (Big. 28) ; Itugnur
Olsson, Stockholm (Fig. 30).
I thank iilso the authors of t,hese illustrations who liavc givtbn
pcmiiasion for their rcyrodiic4ioi1 i i n t l whose iiiimrs uplwnr in the
relevcult ( y t ioiis.