. A biology of Crustacea. Crustacea. PARASITIC CRUSTACEA 121 The larval form of the gnathiids is quite a normal looking little isopod, but its mouthparts are modified for piercing and sucking the blood of fish. One such larva, Praniza milloti, has been found attached to the coelacanth, Latimeria. After the larva has gorged itself the third, fourth and fifth thoracic segments are distended to about twice the diameter of the rest of the body. The larvae probably remain parasitic for several months, after which they leave their hosts and take up residence in adult quarters. The adult male has a v
. A biology of Crustacea. Crustacea. PARASITIC CRUSTACEA 121 The larval form of the gnathiids is quite a normal looking little isopod, but its mouthparts are modified for piercing and sucking the blood of fish. One such larva, Praniza milloti, has been found attached to the coelacanth, Latimeria. After the larva has gorged itself the third, fourth and fifth thoracic segments are distended to about twice the diameter of the rest of the body. The larvae probably remain parasitic for several months, after which they leave their hosts and take up residence in adult quarters. The adult male has a very large head and mandibles, but the other mouth- parts are reduced and do not function. Neither male nor female feed in the adult state. The females are less modified than the. Fig. 53. Head of a larva of Para gnat hia formica (Isopoda, Family Gnathiidae). Only the bases of the antennae are shown. m = mandible. mx = maxilla. males; they brood their eggs in internal sacs, and die when their larvae have been released. The Gnathiidae are quite a separate group from the Epicaridea, and they do not help in trying to trace the evolution of the latter group. More help is given by members of the family Cymothoidae. These are also parasitic on fish, but only as adults. In some cymo- thoids the females are somewhat asymmetrical when mature, recalling the asymmetry found in the Bopyridae. Another interest- ing feature is that the males often develop into females later in life, showing that the sex is not very strongly determined, and indicat- ing how the lability of the sex in the Bopyrids may have Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Green, J. (James), 1928-. Chicago, Quadrangle Books
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Keywords: ., bookcentury1900, bookcollectionbiodiversit, booksubjectcrustacea
