A transverse section of the cortex of Conchophthirus curtus reveals details of cortical structure. This includes the nature of the cell membrane and the alveolar membranes that reside immediately below the surface; fibrillar and microtubular structures that support this ciliated cell, and in the case of Conchophthirus, the cortical mitochondria that may represent a single mitochondrion that has finger-like extensions that lie immediately between the rows of basal bodies and are independent of more typical vesicular mitochondria that reside in the inner cytoplasm. Details of the basal bodies are revealed. The negative magnification is 15,000X. The raw film was scanned with an Epson Perfection V750 Pro. This image is best used for quantitative analysis. For greater detail see:Antipa, G. A. 1971. Structural differentiation in the somatic cortex of a ciliated protozoan, Conchophthirus curtus Engelmann, 1862. Protistologica 7:47l-501.