Ocelli sentence example
The ocelli are seen in FIG.
Ocelli are seen at the base of the tentacles, and also (as an exception) groups of medusiform buds.
The sense organs are typically ocelli, never otocysts.
Ocelli, if present, are borne on the tentacle-bulbs.
Above is the crown (vertex or epicranium), on which or on the " front " may be seated three simple eyes (ocelli).Advertisement
Most insects possess a pair of compound eyes, and many have, in addition, three simple eyes or ocelli on the vertex.
The head is rather large, and is furnished at first with five simple eyes of nearly equal size; but as it increases in size the homologues of the facetted eyes of the imago become larger, whereas those equivalent to the ocelli remain small.
Lateral eyes, when present, represented by separate ocelli.
The broad head carries, in addition to the prominent compound eyes, three simple eyes (ocelli) on the crown, while the feeler consists of a stout basal segment, followed by five slender segments.
The sense-organs are covered over by flaps of the umbrellar margin (hence " Steganophthalmata "), and are always tentaculocysts, that is to say, reduced and modified tentacles, which bear usually both ocelli and otocysts, and are hollow.Advertisement
The more proximal portion of the rhopalium usually bears one or more ocelli (oc).
As a further advance, the pit becomes widened out into a cup, as in the lateral ocelli of Charybdaea.
The histological structure oc', oc 2, Distal and proximal median of the Scyphomedusae is in ocelli.
The larvae are white, fleshy, apodal grubs, with a series of tubercles along each side of the body; the head is round, and bears strong jaws, and sometimes rudimentary ocelli.
One of the most obvious features is that some feathers end in an apparent eye or ocellus (plural ocelli ).Advertisement
The ocelli occur usually either on the inner or outer sides of the ten tacles; if on the inner side, the tentacle is turned upwards and t ®Q carried over the ex - umbrella so ®m r s ???.
As has been described above, the endoderm may also contribute to the sense-organs, but such contributions are always of an accessory nature, for instance, concrement-cells in the otocysts, pigment in the ocelli, and never of sensory nature, sense-cells being Hydromedusae are of separate sexes, the only known exception being Amphogona apsteini, one of the Trachomedusae (Browne ).
The young are prettily spotted with white and black ocelli, but the coloration of the adult is mostly very plain.