SOME ASPEOTS OF PHOTORECEPTION AND VISION IN FISHES
173
of adults. No doubt the paired eyes play other roles in phototactic and
directed activities (Young, 1935a, b).
Integumentary photoreceptors are presc-nt in blind cave fishes, but
none was found in marine fishes examined by Parker (1909). Howover,
there is evidence that the pineal body (Fig. 1) or the pineal coniplex
(which term refers to the pined body anti adjoining brain tissus) is
photosensitive in many teleosts. It has long been known that the
melanophores of the minnow Phozinua disperse when its pineal is
stimulated by light, and the pineal also influences photokinesis. Since
photosensitivity is not completely abolished by destruction of the
FIQ. 1. Vertical section through the middle of tho pined region of the cstfih (A7nleiwurs).
Legend : ES, spiphyeeal stalk ; EV. epiphyw a1 vwiclo ; I'C, pontrtrior wirirriinaurti ;
S, euperior commimre. ~ 2 9 0 . (From Terry, l(r10.)
pineal, it has been postulated that thcrc: arc additional ph"tort:c~ptr,m
in the wall of the diencephalon (vnn f'rbch, I!)] I ; Hchrtrror, I!t2H).
Breeder and Rasquin ( 1 947) have Hhowii that t h o pirical in conwrrit~d
with photokinwis in Mind characim ( A noptichlhp) from O ~ V U N ant1 they
(1950) have distinguished three group of i,cleoHtH according to the
character of the pineal covering. Thcw iLrc . ( I ) f i H f \ m with tranrtliit:t:rit
tissue over tho pineal (mostly light-ponitivc) ; (2) fisheH that have
chromstophorm on the surface of the head, which control light reaching
the pineal (these fishes have changeable responses to light) ; (3) fishes
with a permanently covered pineal area (light-negative) ; and some
exceptions. In some fishes, which were blinded and which had the
pineal area covered, light still exerted some effect, albeit to 8 reduced
173
of adults. No doubt the paired eyes play other roles in phototactic and
directed activities (Young, 1935a, b).
Integumentary photoreceptors are presc-nt in blind cave fishes, but
none was found in marine fishes examined by Parker (1909). Howover,
there is evidence that the pineal body (Fig. 1) or the pineal coniplex
(which term refers to the pined body anti adjoining brain tissus) is
photosensitive in many teleosts. It has long been known that the
melanophores of the minnow Phozinua disperse when its pineal is
stimulated by light, and the pineal also influences photokinesis. Since
photosensitivity is not completely abolished by destruction of the
FIQ. 1. Vertical section through the middle of tho pined region of the cstfih (A7nleiwurs).
Legend : ES, spiphyeeal stalk ; EV. epiphyw a1 vwiclo ; I'C, pontrtrior wirirriinaurti ;
S, euperior commimre. ~ 2 9 0 . (From Terry, l(r10.)
pineal, it has been postulated that thcrc: arc additional ph"tort:c~ptr,m
in the wall of the diencephalon (vnn f'rbch, I!)] I ; Hchrtrror, I!t2H).
Breeder and Rasquin ( 1 947) have Hhowii that t h o pirical in conwrrit~d
with photokinwis in Mind characim ( A noptichlhp) from O ~ V U N ant1 they
(1950) have distinguished three group of i,cleoHtH according to the
character of the pineal covering. Thcw iLrc . ( I ) f i H f \ m with tranrtliit:t:rit
tissue over tho pineal (mostly light-ponitivc) ; (2) fisheH that have
chromstophorm on the surface of the head, which control light reaching
the pineal (these fishes have changeable responses to light) ; (3) fishes
with a permanently covered pineal area (light-negative) ; and some
exceptions. In some fishes, which were blinded and which had the
pineal area covered, light still exerted some effect, albeit to 8 reduced