@article{oai:ir.soken.ac.jp:00004172, author = {蟻川, 謙太郎 and EGUCHI, Eisuke and ARIKAWA, Kentaro and ISHIBASHI, Satomi and SUZUKI, Tatsuo and MEYER-ROCHOW V., Benno}, issue = {2}, journal = {Zoological science, Zoological science}, month = {Apr}, note = {In the crab, Hemigrapsus sanguineus, increase in body size follows an isometric growth pattern. All parameters such as eye stalk length, number of ommatidia, diameters of ommatidial facets, length and width of compound eye, rhabdom lengths, and chromophore content exhibit a linear relationship with carapace width ranging from approximately 5-31mm. Eye width increases at a greater rate than eye length. The compound eye growth is accompanied by a narrowing of interommatidial angles, which is likely to lead to a foveal region and improves resolution in the eye of bigger specimens. The volume of retina per a compound eye increases rather exponentially than linearly. The circadian change in rhabdom occupation ratio, the diameter of microvilli as well as the intramembranous particle density are all independent of crab body size. Calculations of the amounts of visual pigment show that in larger crabs extra-rhabdomeric chromophore levels are higher than in smaller crabs. The precise location and the function of the extra-rhabdomeric chromophore remain enigmatic. A study on regional morphological differences in ommatidial organization indicated that the medial region where the facets are the smallest may be the most probable site of the development of new ommatidia with each moult.}, pages = {241--250}, title = {Growth-Related Biometrical and Biochemical studies of the Compound Eye of the Crab, Hemigrapsus sanguineus : Physiology}, volume = {6}, year = {1989} }