Pacific Salpidae — YoUNT 
289 
Salpa dolicosoma Todaro, 1883: 41. 
Salpa dolkosoma-virgula Traustedt, 1885: 360. 
Helkosalpa virgula Todaro, 1902: 405. 
Cyclosalpa virgula Apstein, 1906Z?.’ 161; Ihle, 
1935: 527-529; Ihle and Ihle-Landenberg, 
1936: 274; Thompson, 1948: 118. 
Salpa {Cyclosalpa) virgula Streiff, 1908; 15; 
Metcalf, 1918: 43; Sewell, 1926: 73; Stiasny, 
1926: 418. 
[non] Cyclosalpa dolkosoma-virgula Traustedt, 
1893. 
[non] Salpa {Cyclosalpa) virgula Komai, 1932: 
70. 
SOLITARY form: One specimen examined 
with length of I4l mm. (Fig. lap). Test: The 
test of this specimen is relatively huge 
compared with the body. Volumetric meas- 
urements were made by water displacement: 
the body measured 10 milliliters, whereas the 
test measured 148 milliliters. This great dif- 
ference in volume has not been reported be- 
fore, thus perhaps it is only an anomaly. Test 
globular, gelatinous, thick and flabby; slightly 
glutinous; formed of an outer thin mem- 
branous layer and a thick inner gelatinous 
layer; loosely attached to the body by a few 
fine strands of test tissue; without permanent 
elevations or ridges. Posterior languets shown 
by Metcalf (1918) not present in POFI spec- 
imen, but a pair of short test projections 
present at the cloacal region. Muscles: M I 
and VI are continuous dorsally on each side, 
forming two dorsal longitudinal muscles; M 
I extending posteriorly on ventral surface 
forming two ventral longitudinal muscles 
that end at region of stolon extrusion; M V 
interrupted dorsally, extending ventrally al- 
most to stolon level as an anteriorly directed 
longitudinal muscle, thus almost meeting the 
posteriorly extended M I; M II, III, IV, and x 
dorsally and ventrally interrupted; M I join- 
ing mouth muscles. The close relationship of 
this species and H. komaii is evident from the 
similarity of muscle structure. It can easily be 
distinguished from it, as H. virgula possesses 
two dorsal longitudinal muscles rather than 
Fig. 7. Helicosalpa virgula. a, solitary form, dorsal 
aspect; b, solitary form, ventral aspect {a and b schem- 
atic, not showing the test; length, I4l mm.); c, aggre- 
gate form, sinistral individual from stolon, dorsal 
aspect; d, aggregate form, dextral individual, dorsal 
aspect (after Ihle, 1937-39, modified from Streiff, 
1908 ). 
