Biologists at the City College of New York are requesting matching funds to purchase a transmission electron microscope (TEM). The new TEM will replace a Phillips 300 purchase 26 years ago. The research aided by the new equipment is quite broad in aspect, covering fields such as Neurobiology, Molecular Developmental Genetics, Immunobiology, Protistology, Molecular Systematics, Endocytobiology, and Evolution. More specifically the following projects will be aided: 1) Phagosome- phagolysosomal processing in diatom-bearing endosymbioses in foraminifera; 2) Karyokinesis and systematics of foraminifera; 3) Molecular systematics of planktonic diatoms; 4) Cell surface phenotypes of thymic nurse cells; 5) Contact between thymocytes and thymic nurse cells; 6) Molecular and genetic analysis of the Drosophila compound eye; 7) Molecular mechanisms underlying axonal development and connection specificity in the embryonic and metamorphosing nervous system of the frog Xenopus laevis; and 8) Studies of growth factors and neurotransmitters involved in the signal cascade by means of which the retina modulates growth of the sclera which, when awry, can lead to myopia.