to each other. Like Oncinopus, the genus Macrocheira also has a seven-segmented abdomen and a basal segment of antennae that is mobile. Macrocheira also has orbital parts, the eye socket and features around it, that are similar to differentiated genera. Another differentiating feature is the supraorbital eave. It is part of the orbital region above the eyestalks. It projects laterally and becomes part of the spine. From the anatomical observations of this genus and others in the family Inachidae, Macrochiera was placed in the family Inachidae, descending from the genus Oncinpus and from it descending the genera Oreconia, Parapleisticantha, and Pleistincantha. Anatomy M. kaempferi is a giant crab with a pear-shaped carapace that is 350 mm (13.7 in) when measured on the median line. Its surface is covered in small spike-like projections or tubercles. The spine of an adult giant crab is short and curves outward at the tip. The spines in young giant crabs, though, are long compared to their carapaces, along with an uncurved spine. This proportionality explains, as in other decapod crustaceans, that spine size decreases as specimens grow older. As mentioned in the taxonomic section, this genus contains the family's primitive feature of a movable antenna at the basal segment, but "the development of a spine at the posterior angle of the supraocular eave, and the presence of intercalated spine and antennulary septum seem to attribute a rather high position to this genus." Lastly, differences are seen between the sexes. Adult males have very long front legs where the claws are located, but they are still shorter than the ambulatory legs of females, located in the back of the carapace. Fishery and conservation Temminck, in his original description, noted that the crab was known to the Japanese for the serious injuries it can cause with its strong claws. The Japanese spider crab is "occasionally collected for food", and even considered a delicacy in many parts of Japan and other areas in the region. In total, were collected in 1976, but fell to only in 1985. The fishery is centred on Suruga Bay. The crabs are typically caught using small trawling nets. The population has decreased in number due to overfishing, forcing fishermen into exploring deeper waters to catch them. The average size caught by fishermen is a legspan of . Populations of this species of crab have diminished over recent years and many efforts are being