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PACIFIC SCIENCE, Vol. IX, April, 1955 
convoluted formation of the dorsal tubercle 
and the looped nature of the gut. The caecum 
is large and projects posteriorly much like 
that found in C. bakeri. The arrangement of 
the testis is reminiscent of that found in C. 
virgula in that it extends back from the center 
of the gut loop in a long slender pouch. 
The terminal openings and long muscular 
peduncle differentiate this species from all 
other members of the genus Cyclosalpa except 
C. pinnata and C. bakeri. The absence of light 
organs differentiates C. strongylenteron from 
C. pinnata and the convoluted dorsal tubercle 
and formation of the body muscles distin- 
guish it from C. bakeri. 
Body: (Fig. 1) The general shape of the 
body is much like that of the aggregate gen- 
eration of C. afftnis. The size is from 2 to 100 
mm. The test is soft, thick and very easily 
stripped from the animal. The atrial and oral 
openings are terminal. Many specimens have 
the dorsal portion of the body covered with 
a granular material which makes the details 
of structure difficult and sometimes impos- 
sible to see. 
Fig. 1. Cyclosalpa strongylenteron , aggregate genera- 
tion. AO, Atrial opening; C, caecum; DT, dorsal tubercle; 
GG, dorsal ganglion; IM, intermediate muscle; Li-L 2 , 
sphincters of the lower lip; M, oral opening; OE, oeso- 
phagus; pd, peduncle; T, testis; Ui-U 3 , sphincters of the 
upper lip; vm, dorsal visceral muscle; vm', ventral 
visceral muscle; i-iv, body muscles. 
Light organs: Light organs are absent. 
Muscles: (Fig. 1) There are four body mus- 
cles arranged much like those of C. pinnata. 
All the body muscles are continuous across 
the dorsal midline, while ventrally only mus- 
cle IV is continuous with its mate from the 
opposite side. Body muscles I and II are in 
contact both dorsally and ventrally, extending 
ventrally into the peduncle as the paired 
posterior peduncle muscles. Muscle IV gives 
off two branches, the first the ventral visceral 
muscle, originates ventrolaterally and extends 
back along the intestine. The second, the 
dorsal visceral muscle, originates just below 
the lateral midline and extends posteriorly 
and ventrally into the center of the loop 
formed by the gut. Just above the origin of 
the dorsal visceral muscle the atrial retractor 
attaches to muscle IV ; from whence it extends 
back to insert into the first, and strongest, 
atrial sphincter. The atrial sphincter muscles, 
which number about 13, are unbranched and 
form complete loops. 
The oral musculature closely resembles that 
of the aggregate C. pinnata. There is a single 
oral retractor which passes forward, external 
to the intermediate muscle, and bifurcates to 
form the two sphincters of the lower lip. The 
upper lip has three sphincters, the first ori- 
ginates from the first sphincter of the lower 
lip just after its formation. The second and 
third originate from the intermediate muscle 
just above the point where it is crossed by the 
oral retractor. From the point of origin of the 
sphincters the intermediate muscle bends back 
to attach to the dorsal portion of the first 
body muscle. The horizontal muscle extends 
from the intermediate muscle, just before the 
junction of that muscle with body muslce I, 
to a point on the third sphincter of the upper 
lip about midway between its origin and the 
dorsal midline. Ventrally the intermediate 
muscle joins its mate from the opposite side 
to form a V which extends into the peduncle 
as the anterior peduncle muscle. 
