322
KOHMAN Y. ARAKAWA
the range 0 . 7 3 mm-1-00 mm.”
Fig. 41 .) (Pellet-type 111- 10).
16. A . ltroughtoni (Schreack) (PI. 1-4)
Faecal ribbons of this and the above species are so much alike that
it is impossible to draw a sharp distinction between them. They are
ribbon-shaped with no external sculptures. Both edges are thickened
and slightly upturned. There is a localization of materials ; the coarse
matter concentrates towards the centre and the finer particles lie in
the lateral regions (Pellet-type 111-10).
Locality : Himeji, Hyogo, Japan.
Measurements : For an animal with shell 85-0 mm long, the ribbons are
3.5 mm in average width.
17. Striarca (Didimacar) symmetrica (Reeve) (Pl. 5-53)
The pellets of this species are very similar in type to those of
Area and Anadara. They have no grooves and ridges. They are light
greyish-yellow in colour and rather coarse in texture (Pellet-type 111-10).
Locality : Mukaishima, Hiroshima, Japan.
Measurements : The ribbons shed by an animal with a shell 9.0 mm long
are 0.26 mm in average width.
1 8. Barbatia (Xavignyarca) virescens (Rve)
The ribbons are normally ungrooved, but occasionally may possess
a shallow mid-ventral groove. On the other side, they are slightly
raised along the median line to form a low mid-dorsal ridge. Both edges
are turned dorsal-wards and the section is bi-crescentic (Pellet-type
Locality : Tomioka, Kumamoto, Japan.
Measurements: For an animal with shell 23.0 mm long, the average
width of the ribbons is 0.84 mm.
19. B. (8.) v. obtusoides (Nyst) (Pl. 1-3 and P1. 4-36)
“ The pellets are ribbon-shaped, about 0.73 mm in width. There
are no prominent surface sculptures, but five or six obscure longitudinal
striae on each side. They are soft and fragile in consistency and somewhat coarse in texture. The pellets are loosely packed with fairly
coarse materials.” (Arakawa, 1965, p. 15, P1. IV, Figs. 40, 46.) (Pellettype 111-10).
(Arakawa, 1965, pp. 14-15, P1. I V ,
111-10 (IlOa)).
KOHMAN Y. ARAKAWA
the range 0 . 7 3 mm-1-00 mm.”
Fig. 41 .) (Pellet-type 111- 10).
16. A . ltroughtoni (Schreack) (PI. 1-4)
Faecal ribbons of this and the above species are so much alike that
it is impossible to draw a sharp distinction between them. They are
ribbon-shaped with no external sculptures. Both edges are thickened
and slightly upturned. There is a localization of materials ; the coarse
matter concentrates towards the centre and the finer particles lie in
the lateral regions (Pellet-type 111-10).
Locality : Himeji, Hyogo, Japan.
Measurements : For an animal with shell 85-0 mm long, the ribbons are
3.5 mm in average width.
17. Striarca (Didimacar) symmetrica (Reeve) (Pl. 5-53)
The pellets of this species are very similar in type to those of
Area and Anadara. They have no grooves and ridges. They are light
greyish-yellow in colour and rather coarse in texture (Pellet-type 111-10).
Locality : Mukaishima, Hiroshima, Japan.
Measurements : The ribbons shed by an animal with a shell 9.0 mm long
are 0.26 mm in average width.
1 8. Barbatia (Xavignyarca) virescens (Rve)
The ribbons are normally ungrooved, but occasionally may possess
a shallow mid-ventral groove. On the other side, they are slightly
raised along the median line to form a low mid-dorsal ridge. Both edges
are turned dorsal-wards and the section is bi-crescentic (Pellet-type
Locality : Tomioka, Kumamoto, Japan.
Measurements: For an animal with shell 23.0 mm long, the average
width of the ribbons is 0.84 mm.
19. B. (8.) v. obtusoides (Nyst) (Pl. 1-3 and P1. 4-36)
“ The pellets are ribbon-shaped, about 0.73 mm in width. There
are no prominent surface sculptures, but five or six obscure longitudinal
striae on each side. They are soft and fragile in consistency and somewhat coarse in texture. The pellets are loosely packed with fairly
coarse materials.” (Arakawa, 1965, p. 15, P1. IV, Figs. 40, 46.) (Pellettype 111-10).
(Arakawa, 1965, pp. 14-15, P1. I V ,
111-10 (IlOa)).