468 DEPTHS OF THE OCEAN 



is the commonest. With their prehensile claws they climb 

 about among the hydroids and red algae, hooking themselves 

 on by their hind limbs, swaying to and fro for a time, and then 

 catching hold of another branch with their front claws and 

 climbing farther. In fairly sheltered localities we often get 

 among the branches of the hydroids and algse little tube- 

 shaped dwellings constructed out of various materials and 

 inhabited by different species of amphipods,^ and here, too, 

 we meet with some kinds of pycnogonids.^ Beautifully coloured 

 ,.y, nudibranchs (usu- 



^"^^; ''^^'^"-' " ~^ ally species of 



V^T y^olis, and especi- 



^■^^^^^^^ ^ . s ^jj^ yEolis inifo- 



* branc hialis, see 



Fig. 330- Fig. 330) crawl 



^olis rufobranclualis, Johnst. (After Alder and Hancock.) slowlv aboUt and 



feed like the pycnogonids upon the hydroids ; certain kinds of 

 nudibranchs (especially some species of Doris, see Fig. 331, 

 Polycera, etc.) occur chiefly in the winter. Animal groups 

 that are very numerously represented in the algse -vegeta- 

 tion of the littoral zone, though they must be very carefully 

 searched for, are rhabdocoelous turbellaria and several species 

 of Halacarids. There are, in addition, quantities of the young 

 of Myfilus, asterids, 

 etc. Among the 



" roots " of the lamin- 



aria we frequently get 

 Nereis, Ophiopholis 

 aculeata, and borer 

 mussels [Saxicava). 



I n contradistinction ^^^.^ tuberculata, Cm^'V^ftJ; Alder and Hancock. ) 



to Laniinaria hyper- 



borea, which prefers the most exposed situations, where there 

 are waves or strong currents, as well as hard bottom to which 

 to attach itself, we find the eelgrass [Zostera marina) in 

 enclosed sheltered localities (pools, estuaries, etc.) and upon 

 soft muddy bottom. The fauna of the eelgrass is not nearly 

 so rich in species as that of the laminaria, still there are several 

 characteristic forms living mainly, and perhaps exclusively, in 

 its vicinity. There is, for instance, a small whitish semi-trans- 



^ Especially species of the family Podoceridre, characterised by the extremely hairy antennte. 

 - N'yniplioi brevirostre, Phoxichilhihtin fentoi-aii(ni, Phoxichilns spinosus, etc. 



