. Comparative animal physiology. Physiology, Comparative; Physiology, Comparative. Chromatophores and Color Change 699 Crago as are eyestalks from other groups. This principle which is present in Groups I and II, but absent in Group III, has been called Crflgo-"tair'- lightening hormone (CTLH). The information at hand, although indicat- ing the presence of three chromatophorotropins in crustacean sinus glands, does not permit us to decide between two possibilities: (1) species in Groups I and II possess three principles and those of Group III possess two prin- ciples, and (2) all possess
. Comparative animal physiology. Physiology, Comparative; Physiology, Comparative. Chromatophores and Color Change 699 Crago as are eyestalks from other groups. This principle which is present in Groups I and II, but absent in Group III, has been called Crflgo-"tair'- lightening hormone (CTLH). The information at hand, although indicat- ing the presence of three chromatophorotropins in crustacean sinus glands, does not permit us to decide between two possibilities: (1) species in Groups I and II possess three principles and those of Group III possess two prin- ciples, and (2) all possess only two principles, with one of the two differ- ing in physiological properties between Groups I and II, and Group III. The sinus glands of the eyestalks are not the sole sites of production of chromatophorotropins in crustaceans. It is well known that undisturbed eyestalkless specimens of Crago not uncommonly exhibit random color changes. Since Roller's original work, it has been found by a number of in- vestigators that eyestalkless crustaceans may be induced to undergo char- acteristic color changes through the action of blood-borne factors by stimu- lation with electrical or other means of the cut ends of their optic nerves. Crustaceans of Group I are induced to blanch, but whereas blanching under the influence of sinus gland principles includes white-pigment dispersion, by this means the white concentrates. Members of Group III darken, but here, too, the white concentrates as the black disperses, unlike under sinus gland influence. The responses of Crago of Group II are more obviously complex, and its reactions to electrical stimulation of its optic nerve stubs OROUPl ce MLMuoHcres cnoupn Cll*60 ITIAL IteSPOMSe riHAL ST4Tt mo WMiTi tL'icir wMire mjccTto WITH eiTDACT i or NIKVOUS. GROUP rn ee. ucj) o SLACK »nrTt Fig. 265. Schematic representation of the coloration of eyestalkless crustaceans and state of their dominant chromatophores for each of the three differently
Size: 1260px × 1984px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookpublisher, booksubjectphysiologycomparative
