Transmission electron micrograph of cell division in an insect spermatocyte captured in late anaphase - telophase with cytokinesis in progress. The homologous chromosomes appear as darkly stained disc...

Transmission electron micrographs. The upper panel shows a section through a frog nucleated erythrocyte. The nucleus is largely filled with heterochromatin which appears to have a fibro-granular stru...

Figures 234 and 235 from Chapter 7 (Mitochondria) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. During spermiogenesis in insects, mitochondria fuse into a large spherical mass called the nebenkern. ...

Figure 236 from Chapter 7 (Mitochondria) of 'The Cell, 2nd Ed.' by Don W. Fawcett M.D. Fusion of mitochondria during insect spermiogenesis results in the formation of a structure called the nebenkern...

Epithelia of invertebrates contain zona continua and septate junctions not found in mammals. Left, zonula continua from gut epithelium of a flea; right, septate junction from the midgut epithelium of...

Freeze-fracture preparation of a continuous junction on the lateral surface of epithelial cells from the gut of a flea. Meandering ridges appear to be on the P-face of the replica. Figure 80, by Susu...