78 



New York State Museum 



swimming) ; and benthos or bottom dwellers (Greek ben- 

 thos, depths of the sea), whether attached to the sub- 

 stratum or with powers of locomotion over it. In addi- 

 tion to the three primary conditions above, two other con- 

 ditions affect bathymetric distribution : whether the water 

 is salt or fresh and the increase of pressure with depth. 

 The sea or marine realm (halobiotic: Greek halos, sea; 

 bios, life) is one of three organic , realms, the other two 

 being the terrestrial (geobiotic : Greek gea, earth) and the 

 fresh- water (limnobiotic : Greek limne, pool, marsh). 

 The marine realm is further divided bathymetrically or 

 vertically into three subrealms, the littoral, the pefagic 

 and the abyssal (figure 12). 



zone Shallow Sea 



Sea 



Pelade Keaim 

 .-.loo Fapioms__ 



XjLimiFof heavu sTcr/n- 

 u/aire action Effective 



plafir l/fe.f 



200 fathoms 

 ^000 fathoms 



Deep Sea 



' 1 6y$ q a I -Realm) 



Figure 12 Diagram showing the marine realms (modified 

 after Lull) 



