. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHOROID RETE OXYGEN SECRETION 123 border of the choroid rete. Therein it divides into two branches, each supplying a limb of the rete. These branches may ramify into subsidiary branches running toward the rete proper as in the cod (Fig. 2) ; or they may be closely applied to the base of the capillaries and there arborize into stubby twigs at right angles to the main branch, as in bluefish (). In either case, the arterial capillaries of the rete mirabile proper arise abruptly and almost directly from the thick-walled art
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. CHOROID RETE OXYGEN SECRETION 123 border of the choroid rete. Therein it divides into two branches, each supplying a limb of the rete. These branches may ramify into subsidiary branches running toward the rete proper as in the cod (Fig. 2) ; or they may be closely applied to the base of the capillaries and there arborize into stubby twigs at right angles to the main branch, as in bluefish (). In either case, the arterial capillaries of the rete mirabile proper arise abruptly and almost directly from the thick-walled arteries (Fig. 4). The arteries run submerged in the ophthalmic venous sinus (Figs. 3 and 4). The arterial retial capillaries coalesce to form a bed of intermediate arterial vessels which in turn coalesce into the arterial vessels supplying the choriocapillaris. These intermediate vessels are by no means a negligible part of the structure. In Figure 4 we attempt to show them in true proportion; their aggregate volume must exceed considerably the aggregate volume of the capillary vessels of the rete proper. In some larger fishes, most conspicuously in the gempylid, Lepidocybium flavo- hrunncinn, but also in many others, the rete proper is only a thin sheet capping an enormous, tangled but roughly parallel array of coarse intermediate vessels filling much of the back of the eye, suggesting a mass of spaghetti. The efferent arteries break up into fine arteries in the vascular laver underlying the retina ( Fig. 4), and these arteries in turn supply the capillaries of the chorio- capillaris. Ordinarily these vessels are as small as they are portrayed in Figure Ophthalmic venous sinus. Ophthalmic artery Ophthalmic vein Optic nerve Ventral choroidal vein Choroid rete mirabile FIGURE 3. Choroid rete mirable of the bluefish. Right eye viewed from inside the orbit. The ophthalmic venous sinus is shown largely removed to display the underlying Please note that these images are ext
Size: 1567px × 1594px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
