486 POLYDORA HOPLURA. 
of the tufts three or four of these shorter accompany two or three longer forms with attenuate 
and slightly bent tips with very narrow wings. The appearance of these shorter bristles 
indicates that they are simply modifications of the shorter wimged forms in the closely 
allied P. flava. No packets of fine bristles (in the tissues) occur in this species as in 
P. ciliata and P. flava. | 
The hooks (Plate CXX XVIII, fig. 10), as a rule, are only two in number: the main 
fang makes a larger angle with the neck than in P. flava. The segmental organs are 
coloured brownish-green (Mesnil). 
De St. Joseph describes an enlargement of the alimentary canal from the fifteenth to 
the twentieth segment, with thick muscular walls like a gizzard, as indeed Marion had formerly 
mentioned apparently in the same species. This is probably the pharynx of Mesnil. The 
bundles of fine bristles, so conspicuous in P. ciliata, are absent. 
Cirsted says'—‘‘ Leucodorum cecum 13” longo, #’” lato, rubescente, 70—80 segmentus 
constante ; anterioribus segmentis 3-plo latioribus quam longis, posterioribus, vero duplum 
longioribus granulatus, rostro capitis in duos acuminatas producto, oculis nullis, appendicibus 
tentacularibus acuminatis, segmento quinto acicilis 6—7 preedito. 
“Tn freto Oresund prope inulam Hseen in fundo argillacio.” 
The habitat of P. ceca seems to be different, for it is chiefly a northern form, whilst 
P. flava is more a southern type. 
Hornell found at Jersey numerous examples with their tubes imbedded in a sponge 
(Microciona plumosa, Bowerbank), even so many as forty in a square inch. He does not 
mention the structure to which the sponge was attached, nor whether the tubes were solely 
in the sponge, but the observation is interesting. 
Potypora GiARDI, Mesnil. Plate CX XXVIII, figs. 11 and 1la—large hooks of the fifth 
foot. 
This was represented by a single compressed and more or less dried example kindly 
sent by Mr. Southern. Procured in laminarian roots, Blacksod Bay, March 15th, 1911. 
Externally it shows the frontal lobes of the median process as two conspicuous leaf-like 
projections, which differ from those of the ordinary adult P. ciliata. The branchize in this 
small specimen appeared to be large and flattened, commencing on the seventh or eighth 
bristled segment, but as the specimen was ruptured their exact distribution could not be 
made out. The hooks of the fifth foot seem to have a proportionally longer process than 
in P. ciliata below the terminal curve (Plate CX XXVIII, figs. 11 and lla). The posterior 
bristles are in the usual two groups, a longer series with slightly curved and finely tapered 
tips and narrow wings, and a shorter series with broader wings and tips, which also are 
slightly curved. Those projecting through the skin resemble spines. 
POLYDORA HOPLURA, Claparede. 
At least eighteen posterior segments have the powerful chitinous ventral hooks, the 
first of the series being smaller and less curved, and the terminal also being smaller, though 
1 «Annul. Dan. Consp.,’ p. 39. 
