Some of the peculiarities of structure observed in deep-sea Crustacea seem to be correlated with the difficulties of resting or moving about with security on the soft ooze of the sea-floor. Among the Crabs we find a preponderance of long-legged species, not only among the true Spider Crabs (Oxyrhyncha), but also in other groups (Dromiacea like _Latreillia_, figured on Plate XIX., and Oxystomata), the members of which assume the same spider-like form. In some cases the legs are fringed with long stiff hairs, which may help to prevent the animal from sinking in the ooze, and the spines on the body and legs of many species may have the same effect. Among the deep-sea Prawns, the species of the family Nematocarcinidæ (Plate XVII.) have extremely long and slender legs, which we may assume to be used like stilts for walking over the soft ooze. [Illustration: _PLATE XVII_ A DEEP-SEA PRAWN, _Nematocarcinus undulatipes_. (SLIGHTLY REDUCED) (_From Brit. Mus. Guide_)] Not much is known regarding the food of deep-sea animals. In the absence of plant-life they must of necessity be all carnivorous, and all ultimately dependent on the food-supply falling from above. Some species have been found to have the food-canal filled with Globigerina ooze, which they no doubt swallow, as earth-worms do the soil in which they burrow, for the purpose of extracting the nutriment that it contains. In one species of deep-sea Cumacea (_Platycuma holti_), which appears to feed in this manner, the food-canal is coiled, a condition very rare in Crustacea; in all probability this is due to the necessity for an increase of the absorptive surface, since it is common to find such an increase, either by lengthening and consequent coiling of the gut, or by infolding of its walls, in animals that have to swallow large quantities of relatively innutritious food material. Many species, however, no doubt have more selective habits of feeding. The lobster-like _Thaumastocheles_ (Fig. 44), which was dredged by the _Challenger_ expedition in the West Indies at a depth of 450 fathoms, and has since been got from deep water off the Japanese coast, has one of the chelæ enormously enlarged, with long and slender fingers set with spines like the teeth of a rake. It has been suggested that this remarkable claw may be used for raking or sifting the ooze for small animals on which the _Thaumastocheles_ feeds. A similar function may be suggested for the long and spiny first pair of walking legs in the Spider Crab _Platymaia_ (Fig. 45). [Illustration: FIG. 44--_Thaumastocheles zaleucus._ REDUCED. (After Spence Bate.)] [Illustration: FIG. 45--A DEEP-SEA CRAB (_Platymaia wyville-thomsoni_). REDUCED. (After Miers.)]