9. THE CLASS CRUSTACEA
305
without medial spines on basipodite, with three lateral spines on basal
podomere of exopodite, one terminal spine, and five medial setae, also
with three lateral spines and three medial setae on basal podomere of
endopodite ; third leg similar to second leg but with only two lateral
spines on basal podomere of exopodite and a seta on basal podomere
of endopodite which transforms into a plumose seta along its basal
portion but becomes blade-like distally ; fourth leg with three lateral
spines and four medial setae on basal podomere of exopodite, with four
spines and one medial plumose seta on basal podomere of endopodite ;
fifth leg with distal podomere flattened, 0.072 mm x 0.036 mm, with
a seta (0.023 mm long) on its medial border, three setae (0.018, 0-018
and 0.020 mm long) at its tip, and with small spines scattered along it ;
sixth leg absent ; caudal ramus elongate, 0.093 mm x 0.017 mm, with
flattened dorsal seta and remaining setae relatively strong and claviform including one slightly dorsal to midline of ramus, three long setae
a t tip (longest measuring 0-024 mm), and three short setae near base.
Adult male (Fig. 202) with body shape and color similar to female ;
total length 0.612-0-696 mm (average 0.645 mm), greatest width 0.1680-192 mm (average 0.183 mm); base of first leg distinctly separated
from head; genital segment almost as long as wide, 0.18 mm x 0.112
mm, with posteroventral suture ; ventral surface with a transverse band
of spines near midlength and with row of small spines at each posterolateral margin ; two spermatophores visible, each approximately
0.090 mm x 0-042 mm; abdomen of four segments measuring (from
base to tip) 0.036, 0.031, 0,024 and 0.018 mm respectively; with
transverse rows of small spines along posteroventral margin of segments
except the posteriormost segment which has a group of small spines
near the base of each caudal ramus ; first antenna of seven segments
measuring (from base to tip) 0.018, 0.024, 0.007, 0.011, 0.017, 0.011
and 0.017 mrn respectively; large sensory organ on third and fourth
segment; small sensory organ on fifth and two on basal segment;
second antenna like that of female ; first through fourth legs like those
of female ; fifth leg with flattened distal podomere, 0.042 mm x 0.014
mm, with four setae measuring (from base to tip) 0.016, 0.016, 0.014
and 0.022 mm ; sixth leg composed of two setae, 0.018 mm and 0.017 mm
long ; caudal ramus like that of female.
10. Ostrincola simplex Humes, 1958. (Figs. 203 and 204)
(Order Cyclopoida; family Ergasilidae)
Ostrincola simplex adults were described by Humes (1958b) from the
mantle cavity of oysters, Ostrea sp., off the coast of Madagascar on the
island of Nossi-BB.
A.M.D.-5
20
305
without medial spines on basipodite, with three lateral spines on basal
podomere of exopodite, one terminal spine, and five medial setae, also
with three lateral spines and three medial setae on basal podomere of
endopodite ; third leg similar to second leg but with only two lateral
spines on basal podomere of exopodite and a seta on basal podomere
of endopodite which transforms into a plumose seta along its basal
portion but becomes blade-like distally ; fourth leg with three lateral
spines and four medial setae on basal podomere of exopodite, with four
spines and one medial plumose seta on basal podomere of endopodite ;
fifth leg with distal podomere flattened, 0.072 mm x 0.036 mm, with
a seta (0.023 mm long) on its medial border, three setae (0.018, 0-018
and 0.020 mm long) at its tip, and with small spines scattered along it ;
sixth leg absent ; caudal ramus elongate, 0.093 mm x 0.017 mm, with
flattened dorsal seta and remaining setae relatively strong and claviform including one slightly dorsal to midline of ramus, three long setae
a t tip (longest measuring 0-024 mm), and three short setae near base.
Adult male (Fig. 202) with body shape and color similar to female ;
total length 0.612-0-696 mm (average 0.645 mm), greatest width 0.1680-192 mm (average 0.183 mm); base of first leg distinctly separated
from head; genital segment almost as long as wide, 0.18 mm x 0.112
mm, with posteroventral suture ; ventral surface with a transverse band
of spines near midlength and with row of small spines at each posterolateral margin ; two spermatophores visible, each approximately
0.090 mm x 0-042 mm; abdomen of four segments measuring (from
base to tip) 0.036, 0.031, 0,024 and 0.018 mm respectively; with
transverse rows of small spines along posteroventral margin of segments
except the posteriormost segment which has a group of small spines
near the base of each caudal ramus ; first antenna of seven segments
measuring (from base to tip) 0.018, 0.024, 0.007, 0.011, 0.017, 0.011
and 0.017 mrn respectively; large sensory organ on third and fourth
segment; small sensory organ on fifth and two on basal segment;
second antenna like that of female ; first through fourth legs like those
of female ; fifth leg with flattened distal podomere, 0.042 mm x 0.014
mm, with four setae measuring (from base to tip) 0.016, 0.016, 0.014
and 0.022 mm ; sixth leg composed of two setae, 0.018 mm and 0.017 mm
long ; caudal ramus like that of female.
10. Ostrincola simplex Humes, 1958. (Figs. 203 and 204)
(Order Cyclopoida; family Ergasilidae)
Ostrincola simplex adults were described by Humes (1958b) from the
mantle cavity of oysters, Ostrea sp., off the coast of Madagascar on the
island of Nossi-BB.
A.M.D.-5
20