22? MI 
The body is rather slender and cylindrical in form. The anterior and posterior portions 
of the body are not sharply defined. The exopodite of the antennae is three-jointed. The exopodite 
and endopodite of the first pair of feet are three-jointed as in Dactylopusca, but more slender. 
The exopodite and endopodite of the second, third and fourth pairs of feet are three-jointed 
as in Dactylopusza. The fifth pair of feet is foliaceous and two-jointed. 
Three species belonging to this genus were represented in the material collected by the 
‘Siboga’ in the Malay Archipelago. 
1. Amphiascus havelockt (Thompson and Scott). 
Dactylopusia havelocki Thompson & Scott, 1903, p. 269, pl. IX, figs. 11—18. 
Four females identical with the above species were found in the washings from dredged 
invertebrata collected at Station 273, at a depth of 13 metres. 
This species can readily be recognised by the very broad distal joint of the fifth pair 
of feet of the female. 
Amphiascus havelockt has hitherto only been known from Ceylon. 
2. Amphiascus hirsutus (Thompson and Scott). 
Dactylopusia hirsuta Thompson & Scott, 1903, p. 269, pl. IX, figs. 19—24. 
One female belonging to this species was found in the washings from dredged inverte- 
brata collected at Station 273, from a depth of 13 metres. 
The peculiar pyriform distal joint, and the armature of the proximal joint of the fifth pair 
of feet of the female, readily separate this species from any of the other members of the genus. 
Amphiascus hirsutus has hitherto only been recorded from: Ceylon. 
3. Amphiascus ceylonicus (Thompson and Scott). 
Dactylopusia ceylonica Thompson & Scott, 1903, p. 269, pl. IX, figs. 25—32. 
Females identical with the above species were found in the washings from dredged 
invertebrata collected at the following two stations. 
Stat. 226, 1595 metres, 2 specimens. — Stat. 273, 13 metres, 3 specimens. 
Amphiascus ceylonicus is closely related to Amphiascus havelocki in its general appe- 
arance, and in the structure of its appendages, but it can be distinguished by the distinct 
difference in the proportional length of the joints of the antennules, and by the moderately 
narrow distal joint of the fifth pair of feet of the female. 
This species has hitherto only been known from Ceylon. 
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