Pacific Salpidae — YoUNT 
313 
Salpa (Jasis) hexagona Apstein, 1894^.' 52. 
Jasis hexagona Heider, 1895: 368. 
Salpa {Ritteria) hexagona Metcalf, 1918: 62; 
Sewell, 1926: 87. 
Metcalfina hexagona Ihle and Ihle-Landenberg, 
1933: 199; Ihle, 1935: 527-529; Thompson, 
1948: 129. 
SOLITARY FORM: More than 10 specimens 
examined with length range of 48-117 mm. 
with end projections (Fig. 20). Test: Traustedt 
(1885) figured the test accurately; unfortu- 
nately, his figures were not copied completely 
by Apstein (1906^), Metcalf (1918), and 
Thompson (1948), who left out the test ridges 
so well shown by Traustedt. The description 
of the test here agrees with that of Traustedt, 
but he did not figure or describe the attach- 
ment organs described here. Test firm; one 
posterior projection on each side that contains 
a mantle process which bears a sucker on its 
tip. As Sewell (1926) pointed out, there are 
on each posterior projection five [minutely 
serrated] ridges. They are symmetrically lo- 
cated— one dorsal, two lateral, and two ven- 
tral. The lateral ridges of the projections are 
continuous with the posterior ridge of test 
encircling the cloacal siphon ventrally. There 
are 11 longitudinal ridges — four dorsal, six 
lateral, and one ventral (or four lateral and 
three ventral) — and one circular posterior 
ridge around the cloacal region ventrally, con- 
tinuous with the posterior projections. In 
small specimens, all these ridges bear small 
or minute spines. In large specimens the 
spines are sparse and always minute. Chin and 
gut swelling moderately large. Attachment 
organs are relatively numerous on this soli- 
tary form; one disappears in the largest spec- 
imens. There are two antero ventral attachment 
organs at base of chin; a third, midventral 
and anterior to gut region, interrupts mid- 
Fig. 21. Metcalfina hexagona, aggregate form, a, Whole animal, dorsal aspect; b, scheme of cross section of the 
test at M III level; c, test, ventral aspect; d, test, left side. 
