26 
on their base they carry gonophores (generally each a single one). 
Only so far is there a likeness to Ichthyocodium; for the gonophores 
are not set free as medusæ but remain attached as sporosaes, re- 
sembling those of C/ava, and in the same colony are found male 
as well as female individuals. 
In 1909 Miss Winifred E. Coward (6) described Pirlocodium 
repens, epizoic on the Pennatulid Ptilosarcus sinuosus (Gray) 
(captured by the Siboga-Expedition at 9? 03' Lat. S., 126? 24,5' 
Long. E. in 112 Met. depth); it grows along the free edges of the 
leaves. The colony is dimorphic having two quite distinct forms 
of polypes arising from tubes enclosed in a basal membrane devoid 
of perisarc. The hydranths or "”gasterozooids” are without tentacles, 
naked, and possess a simple mouth-pore; they show no nematocysts 
and reach at most a length of 0,373 mm. More numerous are the 
"dactylozooids” (ca. 0,186 mm. in length), short and broad polypes 
bearing at the terminal end four capitate tentacles crowded with 
large nematocysts; mouth and internal cavity are lacking, the ento- 
derm of the tentacles and body being solid and scalariform. The 
gonophores arise from the base of the hydranths; they are described 
as sporosacs but provided with traces of four radial canals and of 
four rudimentary tentacles on the closed and rudimentary bell, the 
superficial ectoderm of which shows nematocysts; the closed manu- 
brium bears (female) genital cells. According to the description it 
seems to me at least possible that these gonophores are not real 
sporosacs but may carry their development further and eventually 
be set free as medusæ. But even if this should not be the case, 
I think Ptilocodium has no close relationship to Ichthyocodium, the 
latter showing no dimorphism of the polypes; but Ptilocodium 
apparently is closely allied to the Hydroid, which Kåkenthal 
found growing on another Oetactinia. In 1909 Kakenthal de- 
scribed a new Gorgonid from Japan, Anthoplexaura dimorpha (11), 
on which he discovered this epizoic Hydroid (1. c. p. 24); he men- 
tions polypes devoid of tentacles, and others provided with tentacles 
(sections through one of the latter are figured 1. c. Pl. VII, Fig. 37), 
