Geology Reference
In-Depth Information
Image not available due to copyright restrictions
Image not available due to copyright restrictions
5. Trilobites were either blind, as were the agnostid trilobites
(
Hypagnostus parvifrons
), or possessed paired eyes.
Sighted trilobites had one of two types of eyes. Holochroal
eyes are characterized by generally hexagonal-shaped
biconvex lenses that are packed closely together and
covered by a single corneal layer that covers all of the
lenses. This type of eye is similar to a modern compound
eye and results in mosaic vision, such as in the trilobite
Scutellum campaniferum
.
Scutellum campaniferum,
(holochroal eyes)
Image not available due to copyright restrictions
7. Some trilobites had the ability to enroll, presumably to
protect their antennae, limbs, and soft ventral appendages.
By doing so, only the hard exoskeleton would be exposed
to potential enemies and the trilobite could still view its
surroundings. This enrolled specimen is
Pliomera fisheri
(Ordovician age) from Putilowa, Poland.
573
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