The Annals and Magazine of Natural History; Zoology, Botany, and Geology Volume 68, PT. 2 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can usually download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1900 edition. Excerpt: ... pair: they terminate in a very perfect chela of comparatively large size, with the dactylns anterior (or dorsal). The fourth pair reach just beyond the far end of the merus of the third pair: they end in a very much smaller and less perfect chela, with the dactylus posterior (or ventral). The abdomen is a perfectly soft membranous bag, of which the segmentation is quite recognizably, but far from conspicuously, defined. In the male it is symmetrical, though the minute or rudimentary appendages, that are present on one side (right or left) of the 3rd 4th and 5th segments, are represented on the other side only by small tufts of small bristles. In the female its symmetry is lost by the presence, on one side or other, of a large membranous leaf-like lobe that forms a capacious cup-like brood-pouch. The first two pairs of abdominal appendages of the male end in convoluted plates, the second pair working in the grooves formed by the first pair. The telson is quite symmetrical, and lies in the middle line, tucked up against the ventral surface of the abdomen. On either side of it are the quite symmetrical swimmerets of the sixth pair: the basipodite of these has a spine at its posterior angle: both the exopodite and endopodite are narrow slender and falciform, with the anterior edge serrated and the tip spiniform: the exopodite is many times larger than the endopodite. The animal does not inhabit a shell, but is protected by the soft fleshy coenosarc of a colony of Actiniarian polyps. This forms a sort of sheet or blanket, one end of which is tucked round the telson of the crab and is firmly held by the hook-like swimmerets of the 6th abdominal somite and by the folded-in telson, while the corners of the other end are firmly grasped by the...