Pacific Salpidae — YoUNT 279 
Fig. 1. Scheme of the test of a solitary form, a, End aspect (after Stiasny, 1926); b, lateral aspect (modified 
after Delage and Herouard, 1898). ch. Chin; d, cloacal opening; dl, dorsal lip; did, dorsal longitudinal depression; 
dir, dorsal limiting ridge; ep, end projections; gs, gut swelling; Ir, lateral ridge; m, mouth; mvr, midventral ridge; 
vl, ventral lip; vlr, ventrolateral ridge. 
chin — the swelling on the ventral anterior sur- 
face below the ventral lip 
spine— 2 . small, conical protrusion beyond the 
test margin 
projection— dL large protrusion of the test; it is 
never filamentous but may contain a man- 
tle projection 
tentacle— 2 . filamentous protrusion of the test; 
it usually contains a mantle projection 
sucker— 2 . disc-like enlargement at the end of 
the mantle (epithelial) tube in the projec- 
tions of some forms (e.g., Thalia democratica, 
sol.) 
Furthermore, when the terms "ridge,” 
"groove,” etc., are used, they always refer to 
longitudinal ridges and grooves unless stated 
otherwise. 
The general morphology of salps is schem- 
atized in Figure 2 to identify structures in the 
remaining figures. Body muscles are desig- 
nated by Roman numerals from anterior to 
posterior (M III = body muscle three), where- 
as mouth and cloacal muscles are designated 
by letters (A, B, C, and x, y, z, respectively). 
This notation follows that set up by Streiff 
(1908) as used by Ihle (1935, 1937-39), ex- 
cept cloacal muscles are denoted by lower- 
case letters to avoid confusion with body 
muscles. 
In addition to those listed in Figures 1 and 
2 , the following abbreviations are used in the 
other figures: ant, Anterior; bl.f, blood-form- 
ing organ; bm, "baumformiger Fortsfee”; 
bv, blood vessel; cirpr, circular projection; 
cl.fl, cloacal flap; cr, crest (dorsal limiting 
ridge); die, dorsal limiting elevation; dip, 
dorsolateral projection (atrial palp); d.ten, 
dorsal tentacle; el.c, elaeoblast cavity; em, em- 
bryo; /, fold in bottom of pharynx; hft, at- 
tachment organ; ho, hook; in, independent 
muscle; lo, light organ; Ipp, lateral posterior 
projection; mdr, middorsal ridge; mvp, mid- 
ventral projection; ob.gr, oblique groove; ob.r, 
oblique ridge; pa, test patch; ped, peduncle; 
pl.pr, posterolateral projection (tentacle); pr, 
posterior ridge; R, right side; rec, rectum; sn, 
snout; St. at, attachment organ; st.op, opening 
for stolon; tes, testis; tr.d, transverse depres- 
sion; vie, ventrolateral elevation; vlp, ventro- 
lateral projection; vr, ventral ridge. 
Most drawings in this paper do not show 
oral or cloacal muscles, as these are small and 
difficult to place correctly in a drawing of the 
whole animal. They are described and figured 
for most species by Streiff (1908), Metcalf 
(1918), Ihle (1935, 1937-39), and Thompson 
(1948). 
It is probable that further study will show 
that the attachment organs are of considerable 
taxonomic importance. They are only inci- 
dentally described in this paper. 
