48 
PACIFIC SCIENCE, Vol. II, January, 1948 
41 (clump); L 18-41 (clump); Canoe Bay 
(clump); Mist Harbor (clump). 
These localities are within the known range 
in Alaska. Depths range from shore to 125 fm. 
Crucigera irregularis Bush 
Crucigera irregularis Bush, 1904: 234, pi. 25, 
fig. 5, pi. 29, fig. 4, pi. 33, fig. 13, pi. 39, 
fig. 1-5; Berkeley, 1930: 73; Berkeley, 1942: 
73. 
Collections. Stations 60-40 (1); 84-40 (1); 
88-40 (1); 139-40 (1); A 8-41 (1); D 11- 
41 (1). 
Originally described from Juneau, Alaska, 
this species has been reported from British 
Columbia (Berkeley, 1942); the present collec¬ 
tions come from southern and southwestern 
Alaska, in 15 to 39 fm., and from Walrus 
Island, Bering Sea, in 31 to 33 fm. 
Genus Chitinopoma Levinsen, emended 
Type C. groenlandica (Morch) 
The operculum is soft and conical; it is 
covered by a slightly convex, chitinous plate. 
The tube is calcareous, elongate, more or less 
irregularly sinuous, and provided with a strong, 
longitudinal Carina. The tentacular crown has 
six or seven pairs of radioles, each provided 
with long paired pinnae and a longer or shorter 
free distal end. The thoracic collar is high; it 
consists of a pair of dorsal lobes and a broad, 
ventro-lateral portion; a thoracic membrane is 
absent. Thoracic setigerous segments number 
seven. The collar ring is provided with a setal 
fascicle, including special setae with a finlike 
expansion, and geniculate setae. Other thoracic 
segments have notopodia and neuropodia. The 
seta! formula is as follows: thorax with smooth 
geniculate and slender setae in notopodia, and 
flat uncinial plates with about nine teeth in 
neuropodia. Abdominal segments are numerous, 
each is provided with uncinial plates in noto¬ 
podia and only one or two geniculate setae in 
neuropodia. 
The type of the genus, C. groenlandica 
(Morch), was originally named Serpula trique- 
tra Fabricius (1780) (not Linnaeus) and 
originated in Greenland. Morch, in a revision 
of the family (1863: 375), referred this spe¬ 
cies to Hydroides norvegica var. groenlandica. 
Malmgren (1867: 120) raised the variety to 
rank of species, questionably in the genus 
Hydroides. Later, Levinsen (1884: 203) erected 
the genus Chitinopoma, with new species, 
C. fabricii, and referred Serpula triquetra Fabri¬ 
cius to it. As shown by Bush (1904: 229) (in 
footnote), Levinsens name is superfluous and 
must give way to Malmgren’s name. 
In a key to the Serpulidae, Bush (1904: 224) 
placed Chitinopoma Levinsen in the same cate¬ 
gory with Hyalopomatopsis St. Joseph, and dif¬ 
ferentiated them thus: 
Chitinopoma with uncinial plates trapezi- 
form, with appressed teeth, the lowest 
larger than the others. Operculum with 
concave horny plate. 
Hyalopomatopsis with uncini somewhat sim- 
iliar to those in Spirorbis, the teeth longer. 
Operculum with a chitinous or horny cap. 
Actually, these statements reveal no real dif¬ 
ferences, since the opercular caps are convex in 
both cases and the shape of uncinial plates is 
not materially different. Both have a soft oper¬ 
culum with horny, convex cap, and both have a 
high thoracic collar and no thoracic membrane. 
However, the type of Hyalopomatopsis, H. mar- 
enzelleri (Langerhans), has only six thoracic 
setigerous segments; Chitinopoma has seven; 
abdominal setae are geniculate in the latter, not 
so in the former. Capillary setae are present 
only in the second to seventh thoracic setigerous 
segments in Chitinopoma, and presumably pres¬ 
ent in all segments in Hyalopomatopsis (see 
Chamberlin, 1919: 475). The type of Hyalopo¬ 
matopsis originates from abyssal depths in the 
middle east Atlantic Ocean and may be known 
through only a single species. A second species 
which has been attributed to it, H. occidentalis 
Bush (1904: 229), is now referred to Chiti¬ 
nopoma (see page 50). 
