308
KOIIMAN Y . ARAKAWA
characteristic form of these in relation to feeding habits, modes of life
and to the structure and function of the digestive organs. Finally, it
was hoped t o clarify the relations of faecal characters and rate of faecal
discharge to different environmental factors and to speculate on the
evolutionary trends among bivalve groups with regard to the faecal
pellets.
Historical: The earliest detailed description of faecal pellets in any
species of the Bivalvia was given by Dodgson (1928) for Mytilus edulis L.
and the accepted term, “ pseudo-faeces ” originated with him. This
was followed three years later by a series of papers on British molluscan
faeces by Moore (1931, 1931a and 1931b) who gave elaborate descriptions of the pellets in nineteen bivalve species and emphasized the
systematic value of a knowledge of molluscan faeces. Subsequently, he
became concerned with its practical aspects in marine geology and
indicated the importance of the presence of pellets in marine sediments
(Moore, 1933 and 1939). Somewhat briefer descriptions of the pellets
appeared in the work of Edge (1934) on thirty-eight Californian invertebrates including eight bivalves, which was planned with a view to
possible use in palaeoecology. Schafer ( 1953) noticed the palaeoecological importance of the fossil faecal pellets as facies-index and discussed
this possibility in detail for various examples. Moore and Kruse (1956)
assembled scattered reports published up to that time into a review of
“ present ” knowledge of faecal pellets. Manning and Kumpf (1959)
included in their preliminary report on the faecal pellets of the marine
invertebrates from South Florida, descriptions of those of thirteen bivalves. The more recent work of Arakawa (1963 and 1965) on faecal
pellets from Japanese molluscs has embodied descriptions of those in
twenty bivalves. Haven and Morales-Alamo (1965, 1966 and 1966a)
attempted a detailed quantitative investigation into seasonal rates of
faecal and pseudofaecal production in oysters and other invertebrate
filter feeders in relation to ecological conditions, and the terms “ biodeposit ” and b ~ o d e p o ~ ~ t ~ o n
” originated with these authors. Previous
to this, the pioneer work on this line had been carried out by It0 and
Imai (1955) who pursued studies on biodeposition in oyster culture
beds. Ota (1959, 1959a, 1959b, 1959c) and Ota and Fukushima (1961)
also made an extensive survey on the same subject in pearl oyster culture
beds. A somewhat comprehensive review dealing with pellets in all
molluscan classes was made by Arakawa (1962). This was followed
immediately by interesting work by Kornicker (1962) on evolutionary
trends in molluscan faecal pellets. Scattered reports on pellets in various
bivalves were given by Winckworth (1931), Popham (1939), Galtsoff
KOIIMAN Y . ARAKAWA
characteristic form of these in relation to feeding habits, modes of life
and to the structure and function of the digestive organs. Finally, it
was hoped t o clarify the relations of faecal characters and rate of faecal
discharge to different environmental factors and to speculate on the
evolutionary trends among bivalve groups with regard to the faecal
pellets.
Historical: The earliest detailed description of faecal pellets in any
species of the Bivalvia was given by Dodgson (1928) for Mytilus edulis L.
and the accepted term, “ pseudo-faeces ” originated with him. This
was followed three years later by a series of papers on British molluscan
faeces by Moore (1931, 1931a and 1931b) who gave elaborate descriptions of the pellets in nineteen bivalve species and emphasized the
systematic value of a knowledge of molluscan faeces. Subsequently, he
became concerned with its practical aspects in marine geology and
indicated the importance of the presence of pellets in marine sediments
(Moore, 1933 and 1939). Somewhat briefer descriptions of the pellets
appeared in the work of Edge (1934) on thirty-eight Californian invertebrates including eight bivalves, which was planned with a view to
possible use in palaeoecology. Schafer ( 1953) noticed the palaeoecological importance of the fossil faecal pellets as facies-index and discussed
this possibility in detail for various examples. Moore and Kruse (1956)
assembled scattered reports published up to that time into a review of
“ present ” knowledge of faecal pellets. Manning and Kumpf (1959)
included in their preliminary report on the faecal pellets of the marine
invertebrates from South Florida, descriptions of those of thirteen bivalves. The more recent work of Arakawa (1963 and 1965) on faecal
pellets from Japanese molluscs has embodied descriptions of those in
twenty bivalves. Haven and Morales-Alamo (1965, 1966 and 1966a)
attempted a detailed quantitative investigation into seasonal rates of
faecal and pseudofaecal production in oysters and other invertebrate
filter feeders in relation to ecological conditions, and the terms “ biodeposit ” and b ~ o d e p o ~ ~ t ~ o n
” originated with these authors. Previous
to this, the pioneer work on this line had been carried out by It0 and
Imai (1955) who pursued studies on biodeposition in oyster culture
beds. Ota (1959, 1959a, 1959b, 1959c) and Ota and Fukushima (1961)
also made an extensive survey on the same subject in pearl oyster culture
beds. A somewhat comprehensive review dealing with pellets in all
molluscan classes was made by Arakawa (1962). This was followed
immediately by interesting work by Kornicker (1962) on evolutionary
trends in molluscan faecal pellets. Scattered reports on pellets in various
bivalves were given by Winckworth (1931), Popham (1939), Galtsoff