148 
PACIFIC SCIENCE, VoL XVIII, April 1964 
TABLE 1 
Number of Stations at Which Component Species Occurred 
ENIWETOK 
MAJURO 
BIKINI 
SPECIES 
1956 
1957 
1956 
1956 
Polydora armata 
7 
0 
0 
2 
Pseudopolydora antennata 
3 
9 
3 
0 
Polydora tridenticulata 
5 
0 
0 
0 
Pseudopolydora corallicola 
1 
0 
0 
0 
Pseudopolydora pigmentata 
2 
0 
0 
0 
Pseudopolydora reishi 
1 
2 
0 
0 
Tripoly dor a spinosa 
1 
1 
0 
0 
?oncodes (Heydr.) Foslie. Polydora armata has ; 
been described in the past from coralline algae, ; 
sponge, shells of Venus sp. and other lamelli- 
branchs. Okuda (1937:231) says "In the present 
case the species was found in abundance living 
commensally with the coral, Leptastrea pm- i 
purea ” Its widespread occurrence in the habitats 
represented by these collections would indicate 
a form adapted to a fairly wide range of eco- 
logical conditions especially within the limestone 
habitat. 
A ’ 
Pseudopolydora antennata (Claparede) 1870 
Fig. 2(7, 8) 
This species was found at 15 stations, 12 on : 
Eniwetok and 3 on Majuro Atoll. By number 
of specimens it is the dominant form in the 
collections. 
The individuals are attenuated posteriorly, as 
was noted by Fauvel ( 1927) . A specimen which 
measured 0.7 mm wide anteriorly was about j 
one half this width at the posterior end. The 
prostomium is deeply bifurcated, with the lateral 
lobes long enough in some specimens to be 
turned to the side like frontal horns. The carun- 
cle extends to the anterior margin of the modi- 
fied fifth segment on some specimens, to the 
posterior margin of the sixth in some, and to 
intermediate positions in other specimens. With 
limitations, it can be generalized that longer 
specimens have a more posterior extension of : 
Fig. 2. 1-6, Polydora armata. 1, Setae of fifth (after Fauvel, 1927) ><440; 2, setae of fifth, Eniwetok, I 
X660; 3, setae of fifth (after Okuda, 1937) X 1 000; 4, setae of fifth, Eniwetok, ><660; 3 , setae of fifth (P. I 
monilaris Ehlers, 1905) X950; 6, setae of fifth, worn, Eniwetok, X1200. 1 , 8 , Pseudopolydora antennata . j 
7, Setae of fifth (after Fauvel, 1927), X430; 8, setae of fifth, X430. 9—12 , Pseudopolydora corallicola, n. sp . 
9, Anterior end, X 75; 10, hooded hook, X2700; 11, setae of fifth, X600; 12, pygidium, X75. 
that certain polydorids found in her study were 
like P. armata but had branchiae on more seg- 
ments than the originally described form. The 
specimens in this collection generally agree with 
Langerhans (1880) — gills from 7th to 12th; 
Fauvel ( 1927)— gills begin on 7th, 5 to 7 pairs 
only; and Hartman ( 1941)— gills begin on 7th, 
5 to 6 pairs. 
Figure 2 includes a series of drawings of the 
spines of the fifth segment of P armata which 
illustrates the appearance of the structure as 
seen from different angles and at different stages 
of" wear (2, 4 , 6 ) . These drawings are paired 
with comparable figures ( 1 ) from Fauvel (1927), 
(3 ) from Okuda ( 1937 ) , and (3) from Ehlers 
(1905). The third pair of drawings support 
the synonymy of Polydora monilaris Ehlers with 
P. armata (Day, 1954). 
Polydora armata occurred at Eniwetok Atoll 
on the following islands: Aniyaani, Japtan, 
Rigili, Aaraanbiru, and Engebi. It was found at 
Bikini on Enyu. 
P. armata at Eniwetok occurred on both the 
lagoon and ocean sides of the island. It also was 
collected on the close, far, and middle parts of 
the island. It was found in coral rocks from reef 
flats (at one station near the surge zone), on 
the undersurface of rocks, in old coral heads, 
and in rocks in reef flat tide pools; at both 
Eniwetok and Bikini it was collected from coral- 
line algae identified by Reish as Porolitbon 
