They have a very wide bathymetrical range extending from a depth of 250 fathoms (_Polycheles crucifera_) to a depth of 2,000 fathoms (_Willemoesia_). [Illustration: FIG. 18.—_Polycheles baccata_, one of the Eryonidæ. The eyes and eye-stalks are absent, and the margin and sides of the carapace armed with spines. (After Spence Bate.)] But there are many other curious forms of the macrurous crustacea that deserve a passing mention. The graceful _Nematocarcinus gracilipes_, distinguished by the extraordinary length of the antennæ and last four pairs of legs, these appendages being three or four times the length of the body, is by no means rarely met with in depths of over 400 fathoms. The genus _Glyphus_ captured by the ‘Talisman’ is remarkable for the development of a peculiar pouchlike arrangement on the abdomen for the protection of the larvæ during the younger stages of their existence. The proof of the existence of a peculiar cray-fish, _Thaumastocheles zaleuca_, at a depth of 450 fathoms, was one of the most important contributions to carcinology made by the ‘Challenger’ Expedition. The chelæ of this remarkable form are of great but unequal length and armed with long tooth-like spines giving it an appearance not unlike that of the jaws of some carnivorous fish. The shell is soft and the abdomen broad and flattened. There are no eyes nor even eye-stalks, but ‘in front of the carapace,’ as Sir Wyville Thomson remarks, ‘between the anterior and upper edge and the insertions of the antennæ, in the position of the eyes in such forms as _Astacus fluviatilis_, there are two round vacant spaces, which look as if the eye-stalks and eyes had been carefully extirpated and the space they occupied closed with a chitinous membrane.’ The deep-sea prawn, _Psalidopus_, recently taken in 500 fathoms of water by the ‘Investigator,’ affords us an example of a common bathybial character, the whole body being covered with an extraordinary array of sharp needle-like spines. Among the crabs many curious forms have been found in deep water extending down to depths of over 2,500 fathoms. They are nearly all characterised by blindness and a remarkable development of tooth-like spines covering the carapace and limbs. The remarkable _Lithodes ferox_, from a depth of from 450 to 800 fathoms, is perhaps the most perfectly armed crab—in the way of spines—that exists. Every part of the body and limbs is so covered with spines that one has to be extremely careful in handling even a dead specimen.