320
KOHMAN Y. ARAKAWA
Measurements : For an animal with shell 35-0 mm long the rods average
0-70 mm in breadth, and for one 23.0 mm long 0.50 mm.
11. Saccella sematensis Suzuki and Ishizuka (Fig. 5 ~ )
Faecal rods have a single wide longitudinal groove. They are very
fine and homogeneous in texture and greyish-green in colour. At times,
they are chapped by occasional clefts (Pellet-type 11-6).
Locality : Suruga Bay (80 m in depth), Japan.
Measurements : Breadth of the faecal rods shed by an animal of shell
length 10.5 mm is 0.24 mm on the average.
11. SEPTIBRANCHIA (GASTRODEUTEIA)
Faecal pellets in this order were examined for only two representatives belonging to the Cuspidariidae, which are quite indefinable in
shape and may be assigned to Pellet-type 11. Purchon (1958 and 1959)
has suggested the Septibranchia be placed near to the Protobranchia
because of certain similarities between the stomachs of these two groups.
But it appears impossible to support his views from a study of the
faecal pellets".
Cuspidariidae
12. Cardiomya gouldiana septemtrionalis (Kuroda) (Pl. 1-1)
13. Plectodon ligula (Yokoyama) (Pl. 1-2)
Pellets of these two species are similar in nature and appearance.
They are flocculent and blurred in outline, coarse and rather frail in
consistency and translucent. They are normally made up of a jelly-like
substance with admixtures with broken pieces of carcasses, spicules and
other undigested skeletal matter which may possibly be of copepod
origin (Pellet-type 11).
Locality : Chijiwa Bay, off Tomioka, Kumamoto, Japan.
Measurements : For a specimen of C. gouldiana septemtrionalis with shell
8.0 mm long, average breadth is 0.62 mm, and for one of P. ligula with
shell 5.0 mm long it is 0.07 mm.
111. GASTROTRITEIA
Except for the Limopsidae, the representatives of this order may
defecate ribbon-type pellets which belong either t o Pellet-type 10 or
* The description of Hulicardia nipponensis by Nakazima (1967) indicat,es that
septibranchs are specialized eulamellibranchs. (Editorial note-C.M.Y.)
KOHMAN Y. ARAKAWA
Measurements : For an animal with shell 35-0 mm long the rods average
0-70 mm in breadth, and for one 23.0 mm long 0.50 mm.
11. Saccella sematensis Suzuki and Ishizuka (Fig. 5 ~ )
Faecal rods have a single wide longitudinal groove. They are very
fine and homogeneous in texture and greyish-green in colour. At times,
they are chapped by occasional clefts (Pellet-type 11-6).
Locality : Suruga Bay (80 m in depth), Japan.
Measurements : Breadth of the faecal rods shed by an animal of shell
length 10.5 mm is 0.24 mm on the average.
11. SEPTIBRANCHIA (GASTRODEUTEIA)
Faecal pellets in this order were examined for only two representatives belonging to the Cuspidariidae, which are quite indefinable in
shape and may be assigned to Pellet-type 11. Purchon (1958 and 1959)
has suggested the Septibranchia be placed near to the Protobranchia
because of certain similarities between the stomachs of these two groups.
But it appears impossible to support his views from a study of the
faecal pellets".
Cuspidariidae
12. Cardiomya gouldiana septemtrionalis (Kuroda) (Pl. 1-1)
13. Plectodon ligula (Yokoyama) (Pl. 1-2)
Pellets of these two species are similar in nature and appearance.
They are flocculent and blurred in outline, coarse and rather frail in
consistency and translucent. They are normally made up of a jelly-like
substance with admixtures with broken pieces of carcasses, spicules and
other undigested skeletal matter which may possibly be of copepod
origin (Pellet-type 11).
Locality : Chijiwa Bay, off Tomioka, Kumamoto, Japan.
Measurements : For a specimen of C. gouldiana septemtrionalis with shell
8.0 mm long, average breadth is 0.62 mm, and for one of P. ligula with
shell 5.0 mm long it is 0.07 mm.
111. GASTROTRITEIA
Except for the Limopsidae, the representatives of this order may
defecate ribbon-type pellets which belong either t o Pellet-type 10 or
* The description of Hulicardia nipponensis by Nakazima (1967) indicat,es that
septibranchs are specialized eulamellibranchs. (Editorial note-C.M.Y.)