SCATOLOGICAL STUDIES OF THE BIVALVIA (MOLLLJSCA)
345
Measurements : Breadth of pellets shed by an animal with a 10 mm long
shell was 0.54 mm.
Donaciidae
89. Donas variubilis Say
" 1 animal. This individual, 19 mm long, shed a rod-shaped pellet
1.5 mm in length. The width was not determined as the edges of the
pellet were flocculent. It was brown in colour." (Manning and Kumpf,
1959, p. 304.) (Pellet-type 11-4).
v. GASTROPEMPTA
This order comprises six pellet-types ranging from 1-1 to 11-5, with
the highest frequency in 1-1 and 11-4. I n general, the Gastropempta
display the simplest pellets of all the five orders in this class. They
include, besides two common basic types (Types 1-1 and 11-4), several
transitional forms, most of which are characteristic of this group.
Corbiculidae
Type of pellets of this family may belong to 11-4 or to 11-6.
90. Pseudocyrena jloridana Conrad
" 2 animals. One specimen, 27.5 mm long, shed a rod broken into
small pieces up to 1 mm in length. The pellet was slightly compressed
in shape, and had along one surface a shallow canal.
" The canal was made up of darker and coarser material than was the
remaining surface. The rod was 1 mm wide at the widest point. There
appeared to be a concentration of coarser material towards the center."
(Manning and Kumpf, 1959, p. 303, Fig. 4a.) (Pellet-type 11-4 ('26)).
91. Corbicula japonica Prime (Fig. 9 ~ )
Pellets are cylindric and rod-shaped, unsculptured, very fine in
texture and somewhat sandy in appearance. The colour is yellowishbrown (Pellet-type 11-4).
Locality : Lake Shinji, Shimane, Japan.
Measurements : Breadth of pellets fluctuates between 0.20 and 0.34 mm
for an animal with a shell 24.5 mm long.
92. C. leana Prime
Faecal pellets of this and the above species are so much alike that
no clear-cut distinction can be made between them (Pellet-type 11-4).
345
Measurements : Breadth of pellets shed by an animal with a 10 mm long
shell was 0.54 mm.
Donaciidae
89. Donas variubilis Say
" 1 animal. This individual, 19 mm long, shed a rod-shaped pellet
1.5 mm in length. The width was not determined as the edges of the
pellet were flocculent. It was brown in colour." (Manning and Kumpf,
1959, p. 304.) (Pellet-type 11-4).
v. GASTROPEMPTA
This order comprises six pellet-types ranging from 1-1 to 11-5, with
the highest frequency in 1-1 and 11-4. I n general, the Gastropempta
display the simplest pellets of all the five orders in this class. They
include, besides two common basic types (Types 1-1 and 11-4), several
transitional forms, most of which are characteristic of this group.
Corbiculidae
Type of pellets of this family may belong to 11-4 or to 11-6.
90. Pseudocyrena jloridana Conrad
" 2 animals. One specimen, 27.5 mm long, shed a rod broken into
small pieces up to 1 mm in length. The pellet was slightly compressed
in shape, and had along one surface a shallow canal.
" The canal was made up of darker and coarser material than was the
remaining surface. The rod was 1 mm wide at the widest point. There
appeared to be a concentration of coarser material towards the center."
(Manning and Kumpf, 1959, p. 303, Fig. 4a.) (Pellet-type 11-4 ('26)).
91. Corbicula japonica Prime (Fig. 9 ~ )
Pellets are cylindric and rod-shaped, unsculptured, very fine in
texture and somewhat sandy in appearance. The colour is yellowishbrown (Pellet-type 11-4).
Locality : Lake Shinji, Shimane, Japan.
Measurements : Breadth of pellets fluctuates between 0.20 and 0.34 mm
for an animal with a shell 24.5 mm long.
92. C. leana Prime
Faecal pellets of this and the above species are so much alike that
no clear-cut distinction can be made between them (Pellet-type 11-4).