SCATOLOGICAL STVDIES OF THE BIVALVIA ( MOLLUSCA)
327
Locality : Tornioka, Kurnamoto, Japan.
Measurements : Width of t h e ribbons fluctuates between 0.46 and
0.51 mm, for an animal with shell of length 21 mm.
32. M . Jlavidus (Dkr)
Pellets are ungrooved and ribbon-shaped with coarse texture. They
are crescentic in section and greenish-brown in colour. They are usually
voided broken into short pieces (Pellet-type III-lOa ( ? 10)).
Locality : Tomioka, Kumamoto, Japan.
Measurements: Pellets shed by an animal with shell 15 mm long
average 0.22 mm in width.
33. M . plumescens (Dkr)
of the preceding one (Pellet-type III-lOa).
Locality : Mukaishima, Hiroshima, Japan.
Measurements : Average width of the ribbons is 0.5 mm for an animal
of shell length 25.0 mm.
34. Musculus marmoratus (Forbes) (Fig. 4, bottom)
“ This pellet also is in the form of a ribbon, bi-crescentic in section,
but considerably thicker than that of any of the previous species. There
is a wide mid-dorsal ridge, and usually a wide, but not very deep midventral groove, and there may also be lateral grooves on either side of
this, but very variable in position and depth. The ribbon is composed of
fine detritus, and there is no localization of material in it. From an
animal 0.9 em long, the ribbon averages 0.18 mm in diameter.” (Moore,
1931, p. 284, PI. 31, Figs. 13, 14.) (Pellet-type III-l0u).
35. M . (Musculista) japonica (Dkr) (PI. 1-6)
ternal sculpturing is rather indistinct (Pellet-type III- 1 Oa).
Locality : Tomioka, Kumamoto, Japan.
Measurements : Width of the ribbon discharged by an animal of shell
length 13.0 mm averages 0.27 mm.
36. M . ( M . ) perfragilis (Dkr) (Pl. 1-7)
ternal grooves and ribs (Pellet-type III-lOa (?lo)).
This species defecates pellets that are very similar in type to those
Pellets are ribbon-shaped with a bi-crescentic section, but the exI n the faecal ribbons of this species, there is complete absence of ex-
327
Locality : Tornioka, Kurnamoto, Japan.
Measurements : Width of t h e ribbons fluctuates between 0.46 and
0.51 mm, for an animal with shell of length 21 mm.
32. M . Jlavidus (Dkr)
Pellets are ungrooved and ribbon-shaped with coarse texture. They
are crescentic in section and greenish-brown in colour. They are usually
voided broken into short pieces (Pellet-type III-lOa ( ? 10)).
Locality : Tomioka, Kumamoto, Japan.
Measurements: Pellets shed by an animal with shell 15 mm long
average 0.22 mm in width.
33. M . plumescens (Dkr)
of the preceding one (Pellet-type III-lOa).
Locality : Mukaishima, Hiroshima, Japan.
Measurements : Average width of the ribbons is 0.5 mm for an animal
of shell length 25.0 mm.
34. Musculus marmoratus (Forbes) (Fig. 4, bottom)
“ This pellet also is in the form of a ribbon, bi-crescentic in section,
but considerably thicker than that of any of the previous species. There
is a wide mid-dorsal ridge, and usually a wide, but not very deep midventral groove, and there may also be lateral grooves on either side of
this, but very variable in position and depth. The ribbon is composed of
fine detritus, and there is no localization of material in it. From an
animal 0.9 em long, the ribbon averages 0.18 mm in diameter.” (Moore,
1931, p. 284, PI. 31, Figs. 13, 14.) (Pellet-type III-l0u).
35. M . (Musculista) japonica (Dkr) (PI. 1-6)
ternal sculpturing is rather indistinct (Pellet-type III- 1 Oa).
Locality : Tomioka, Kumamoto, Japan.
Measurements : Width of the ribbon discharged by an animal of shell
length 13.0 mm averages 0.27 mm.
36. M . ( M . ) perfragilis (Dkr) (Pl. 1-7)
ternal grooves and ribs (Pellet-type III-lOa (?lo)).
This species defecates pellets that are very similar in type to those
Pellets are ribbon-shaped with a bi-crescentic section, but the exI n the faecal ribbons of this species, there is complete absence of ex-