32 
PACIFIC SCIENCE, Vol. II, January, 1948 
Branchiae are first present from the eleventh 
or twelfth setigerous segment; the first are very 
small but they elongate and widen rapidly 
through six segments and come to be large at 
the beginning of the abdominal region. Pre¬ 
served, many branchiae lack fringe at their outer 
margins, but a few retain a delicate, close pube¬ 
scence that extends distally to a subterminal 
enlargement (Fig. 8 a). 
In the first 14 segments parapodia have an 
elongate, triangular postsetal lobe along the mid¬ 
length of both notosetal and neurosetal ridges. 
These lobes increase in size gradually through 
the thoracic region. From the thirteenth setig¬ 
erous segment another small lobe, resembling 
a ventral cirrus, makes its appearance; it is at 
the lower edge of the neurosetal ridge; it in¬ 
creases in size through four segments, to the 
sixteenth one and is continued back to the 
twenty-second parapodium, where it merges 
with the superior part of a broad parapodial 
flange. At the sixteenth setigerous segment a 
subpodal lobe (Fig. 8 b), located some distance 
below the lower podal one, makes its ap¬ 
pearance. It is usually simple, rarely bifid. This 
subpodal lobe moves gradually more ventrally 
in position; it is continued into the anterior 
abdominal region, through the twenty-third 
parapodium, but is absent thereafter. Intercirri 
are absent. Abdominal parapodia have the pro¬ 
portions shown in Figure 8 a. 
Setae are numerous in thoracic segments; 
those in neuropodia are the denser and disposed 
in transverse series; notopodial setae form a 
tuft. All taper to fine points and are spinous 
along their free length. Abdominal setae are 
similar but fewer in number and slenderer than 
those in front. Furcate setae (Fig. 8 c) are 
present in notopodia. Acicula are pale yellow, 
straight and slender; they terminate distally in 
a point; in abdominal segments they number 
three or four in neuropodia and five or six in 
notopodia. 
H. alaskensis is characterized in having 16 
thoracic setigerous segments. Branchiae are pres¬ 
ent from the eleventh or twelfth segment and 
continued posteriorly to or near the end. Podal 
lobes, resembling ventral cirri, occur on para¬ 
podial segments 15 to 22. Subpodal lobes, widely 
separated from the podal lobes, are on para- 
podal segments 16 to 23. Among the several 
species of Haploscoloplos, only one, H. pana- 
mensis Monro (1933: 1045) from Pacific Pana¬ 
ma, has subpodal lobes, but in it they are not 
continued into the abdominal region and they 
have a position proximal to the podal lobe, not 
widely removed from it, as in H. alaskensis. 
Holotype in the U. S. National Museum. 
Type locality. Lazy Bay, Alaska. 
Distribution. Southern Alaska. 
Haploscoloplos sp. 
Fig. 8 d-f. 
Collection. Murchison Sound, Greenland, in 
60 fm., coll. Capt. R. A. Bartlett (1-). 
One incomplete individual in the collections 
of the National Museum, though not from 
Alaska, seems worth recording since it also 
comes from a far northern locality (Greenland). 
It may represent an undescribed species, but the 
material is too imperfect to ascribe a specific 
name. It consists of 50 anterior segments and 
measures 16 mm. long; greatest width in the 
thorax is about 1.5 mm. The prostomium is 
acutely pointed in the front, somewhat de¬ 
pressed and longer than wide; it lacks eyespots. 
Branchiae are first present in the thorax, from 
the eleventh setigerous segment; they are very 
small at first but increase in size gradually so 
that by the first abdominal segment they are 
larger than the postsetal lobes. The transition 
from thorax to abdomen is at the fifteenth seti¬ 
gerous segment, where neuropodia change char¬ 
acter abruptly, from ridges to tufts. 
Thoracic and abdominal parapodia are pro¬ 
vided with only simple, pointed setae through¬ 
out. Embedded acicula are slender, yellow, and 
few in number. Furcate setae (Fig. 8 /) occur 
with pointed setae in abdominal notopodia; 
they have a smooth stalk. Thoracic setae are in 
full spreading fascicles, densest in neuropodia. 
