THE ABYSMAL ZONE LIFE IN DEEP WATER 



447 



to their dwellings, which consist of water-logged joints of man- 

 grove or bamboo. The large pincers act as a front-door, but a 

 loophole is left between them to serve as a means of observation. 



Certain kinds of crustacean grow to a very much larger size 

 in the deep sea than elsewhere. Among the Slaters (Isopoda), 

 for example, of which the terrestrial wood-lice are the most familar 

 types, we find one species (Bathynomus giganteus] which is a 

 foot long. 



Hedgehog -Skinned Animals (.Echinodermata) of the Deep 

 Sea. Star-Fishes, Brittle-Stars, and Sea- Urchins are all abun- 



Fig. 1302. Deep-Sea Pycnogonid (Colossendeis) 



dantly represented in the abyss, while the beautiful Sea- Lilies 

 (Crinoidea, fig. 1301), the representatives of a once dominant 

 group, are found only in this zone. To this too are restricted the 

 Elasipods, remarkable and apparently primitive types of the Sea- 

 Cucumbers (Hplothuroidea). They have a flattened under sur- 

 face, and creep about like slugs on the soft deposits which cover 

 the sea-floor (fig. 1301). 



Abysmal Sea - " Spiders " (Pycnogonidd). - - These curious 

 jointed-limbed animals, which in the Neritic zone are represented 

 by comparatively small forms, attain relatively colossal propor- 

 tions in the abyss. One of them (Colossendeis) is represented 



in fig. 



Deep-Sea Corals (Anthozoa) and Sponges (Porifera). Some 



