Important agglutinated foraminifera that characterizes the upper bathyal zone
(200-500m) are reported by several workers i.e.
The distribution of conspecific populations in the bathyal zone
and the abyssal zone is in marked contrast with the strict depth zo nation exhibited by endemic groups that inhabit the seep areas off central Japan, namely, bivalves of the genus Calyptogena (Kojima and Ohta, 1997) and vestimentiferans (Kojima et al., 1997b).
Important changes occur in the benthic faunal structure within the large vertical interval of the bathyal zone
. The most obvious difference between shallow and deep-bottoms is the reduction in the number of latitudinal or climatic belts, both in terms of biomass and of faunal structures (Zezina, 1997).