ISSN:
1573-5117
Keywords:
rhabdomeric pigment-cup ocelli
;
lens
;
prolecithophorans
;
plathelminths
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The four eyes of the prolecithophoran Allostoma sp. are disposed in two pairs in a dorsolateral position at the periphery of the brain and beneath its capsule. They are rhabdomeric pigment-cup ocelli. Each eye in the anterior pair consists of one pigment cell and one receptor cell; each in the posterior pair is made up of a larger, single pigment cell and two photoreceptor cells. A lens in front of the pigment cell's aperture is formed by electron-dense, refractive, finger-like protrusions which arise from unpigmented cytoplasmic extensions of the pigment-cup margin. Degenerative signs are sometimes visible in the lens.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00027609
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