Siphonosoma hawaiense , a New Sipunculoid 
from Hawaii (Sipunculoidea) 
S. J. Edmonds 1 
Siphonosoma hawaiense n. sp. 
Figs. 1-4 
Siphonosoma Spengel, 1912; Fisher, 1950 
p. 805; Fisher, 1952 p. 380. 
Specimens and locality: Six specimens 
collected by F. I. Kamemoto on Sept. 29, 1964, 
from hard-packed sand above the level of low 
water near Kualoa, Oahu, Hawaii were kindly 
sent to me for identification by F. G. Eldredge, 
Department of Zoology, University of Hawaii, 
Honolulu. A type specimen has been lodged at 
the Bernice P. Bishop Museum at Honolulu 
(BM numbers: Invertebrate W-294 for the 
type specimen, and Invertebrate W-295 for the 
cotypes) . 
Description: The length of the trunk is 
9-15 cm and the width, which is variable in 
different parts of any of the specimens, is 
3-5 cm. The length of the fully extended in- 
trovert of two specimens is 4-5 cm and the 
width about 2 mm. The colour of the specimens 
preserved in alcohol is pale straw. The skin 
of some of the specimens is very thin and al- 
most transparent; of others it is much wrinkled. 
At the anterior extremity of the introvert of 
one specimen there is a crown of about 50 short 
and fine tentacles. The anterior region of the 
introvert also bears about 30 rows of yellow- 
coloured, blunt spines the shape of which 
resembles to some extent that of a slipper. The 
hooks are about 0.15-0.3 mm long and they 
become progressively smaller the more posterior 
they are placed on the introvert. The introvert 
also bears numerous rings of small yellowish 
papillae which in the anterior region are closely 
associated with the hooks. These papillae are 
about 0.03-0.05 mm in diameter. In the centre 
of each papilla there is a clear circular area 
which is surrounded by a yellowish granular 
region. The papillae on the trunk are of two 
1 Department of Zoology, University of Adelaide, 
South Australia. Manuscript received March 22, 1965. 
kinds: one is small (about 0.03-0.05 mm in 
diameter) and looks very much like those on 
the introvert, while the other is larger (0.25- 
0.40 mm in diameter) but less numerous. The 
latter kind of papilla is largest at the base of 
the introvert and on the posterior surface of 
the trunk. 
The longitudinal musculature is not very 
noticeable externally. When a specimen is dis- 
sected, however, 14-17 well-developed longi- 
tudinal bands of muscles, which anastomose to 
some extent, are observable in the midbody 
region. The circular musculature is continuous. 
Four introvert retractors arise at different levels, 
a dorsal pair more anteriorly from muscles 4-5 
on each side of the nerve cord and a ventral pair 
more posteriorly from muscles 2-3. The dorsal 
and ventral retractors on each side fuse an- 
teriorly to form a single muscle on each side of 
the oesophagus. 
The alimentary canal consists of an oesopha- 
gus, descending and ascending intestinal spirals, 
a short rectum, and an anus. It was filled with 
coarse particles of sand and coral (?) frag- 
ments. An intestinal caecum is present. A polian 
or contractile vessel with wrinkled edges runs 
along the dorsal surface of the oesophagus. 
Strongly developed wing muscles are attached 
to the posterior part of the rectum. A well- 
developed spindle muscle is fastened anteriorly 
to the body-wall in front of the anus and pos- 
teriorly at the terminal tip. The spindle muscle 
gives off anteriorly two strong, wing-like 
strands of muscle which are fastened to the 
body-wall along muscle 5 or 6 on each side of 
the nerve cord near the dorsal retractors. An 
additional fastener arises from the last whorl 
of the intestine and runs to the body-wall at a 
point near the base of the right dorsal retractor. 
Two fine fasteners also run in an almost parallel 
manner from the last whorl of the intestine to 
muscle 1 on each side of the nerve cord at 
points just posterior to the level of attachment 
386 
