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Further Ultrastructural Studies on the Encapsulated Larva of Kronborgia isopodicola (Platyhelminthes, Fecampiidae), with Particular Reference to Nuclei
Author(s) -
Williams J. B.
Publication year - 1995
Publication title -
acta zoologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.414
H-Index - 37
eISSN - 1463-6395
pISSN - 0001-7272
DOI - 10.1111/j.1463-6395.1995.tb00980.x
Subject(s) - neuropil , biology , ultrastructure , anatomy , larva , ontogeny , microbiology and biotechnology , central nervous system , neuroscience , botany , endocrinology
During development of the encapsulated Kronborgia isopodicola larva, nuclei of the body tissues and differentiating eyes undergo a continuous condensation, the progression of which is described. The brain is composed of a central neuropil and an outer layer of nerve cell perikarya. Neurosecretory cells are located at the sides of the brain. Some neurosecretory cell extensions are interposed between the cerebral neuropil and nerve cell perikarya; others overlie the photoreceptor cell processes of the eyes. The advanced encapsulated larva possesses a frontal complex, consisting of modified epidermis, secretory cells, gland ducts and nerve cell processes. The advanced larva is transparent and diminished in size, advantages possibly due in part to the extraordinary process of comprehensive nuclear condensation during ontogeny. The larva has a uniform epidermal ciliation and, while sharing certain features with trochophore larvae, is not of the trochophore type.