SCATOLOGICAL STUDIES OF THE BIVALVIA (MOLLUSCA)
369
Pholadidae
16 1. Pholadidea Eoscombiam Turton
“ The twist in this species is sinistral, but in other molluscs it may
be dextral, i.e. Pholadidea loscombiana, Turton . . ..” (Moore, 1931,
p. 286.) (Pellet-type 11-5.)
162. Barnea (Umitakea) japonica (Yokoyama) (Fig. 1 1 ~ )
Faecal pellets are discoidal in shape with a single spiral cord. This
cord may be absent depending on the nature of the food. The pellets
are frequently shed in chains. The finer constituents lie on the periphery
while the coarser particles concentrate towards the centre. Ratio of
length to breadth of the pellets is 0.48 (Pellet-type 1-la).
Locality : Unknown (Japan).
Measurements when size of producer is 40-0 mm in shell length :
Length of pellet (mm)
0.65 0.70 0.60 0.50 0.60 0.70 0.60
Breadth of pellet (mm)
1.30 1.30 1.30 1.30 1.30 1.30 1.30
Ratio lengthlbreadth
0.50 0.54 0.46 0.38 0.46 0.54 0.46
163. Zirfea gabbi Tryon
ungrooved short rods (Pellet-type 11-4).
Edge (1934, Fig. 4) figured the pellets of this species which form
Xylop haginidae
164. Xylophaga dorsalis Turton
According to Purchon (1941), this species defecates ellipsoid
pellets and has a habit of accumulating the faeces around the mouth
of tubes, giving the appearance of the tubes of Serpula. He states as
follows :
‘‘ The faecal pellets are not expelled with sufficient force to carry
them out of the burrow and so accumulate at its posterior end as a
compact mass, consolidated with mucus, which surrounds the siphonal
process through which the exhalant water current passes. The presence
of this faecal accumulation prevents any extensive movements of the
animal.” (Purchon, 1941, pp. 3, 21, Figs. lb, lla.) (Pellet-type 1-1).
369
Pholadidae
16 1. Pholadidea Eoscombiam Turton
“ The twist in this species is sinistral, but in other molluscs it may
be dextral, i.e. Pholadidea loscombiana, Turton . . ..” (Moore, 1931,
p. 286.) (Pellet-type 11-5.)
162. Barnea (Umitakea) japonica (Yokoyama) (Fig. 1 1 ~ )
Faecal pellets are discoidal in shape with a single spiral cord. This
cord may be absent depending on the nature of the food. The pellets
are frequently shed in chains. The finer constituents lie on the periphery
while the coarser particles concentrate towards the centre. Ratio of
length to breadth of the pellets is 0.48 (Pellet-type 1-la).
Locality : Unknown (Japan).
Measurements when size of producer is 40-0 mm in shell length :
Length of pellet (mm)
0.65 0.70 0.60 0.50 0.60 0.70 0.60
Breadth of pellet (mm)
1.30 1.30 1.30 1.30 1.30 1.30 1.30
Ratio lengthlbreadth
0.50 0.54 0.46 0.38 0.46 0.54 0.46
163. Zirfea gabbi Tryon
ungrooved short rods (Pellet-type 11-4).
Edge (1934, Fig. 4) figured the pellets of this species which form
Xylop haginidae
164. Xylophaga dorsalis Turton
According to Purchon (1941), this species defecates ellipsoid
pellets and has a habit of accumulating the faeces around the mouth
of tubes, giving the appearance of the tubes of Serpula. He states as
follows :
‘‘ The faecal pellets are not expelled with sufficient force to carry
them out of the burrow and so accumulate at its posterior end as a
compact mass, consolidated with mucus, which surrounds the siphonal
process through which the exhalant water current passes. The presence
of this faecal accumulation prevents any extensive movements of the
animal.” (Purchon, 1941, pp. 3, 21, Figs. lb, lla.) (Pellet-type 1-1).