Pacific Salpidae — YouNT 
293 
not accompany the gill; (2) there are no dis- 
tinct light organs present in either form (the 
gut of some species produces light from dif- 
fuse bodies); (3) the gut in the aggregate 
form is a more or less compact "nucleus,” 
never a loosely formed loop or an extended 
tube; (4) attachment organs in the aggregate 
form are separated, not united into one pro- 
cess; thus, there are two or more attachment 
organs in each animaL 
Genus Brooksia Metcalf, 1918 
Solitary form with six body muscles, ag- 
gregate form with four and five. Solitary form 
with an anterior snout containing two pairs 
of longitudinal muscles, the dorsal pair con- 
tinuous with the mouth musculature, the 
ventral pair formed by M I and C.^. Ventral 
longitudinal muscles extend posteriorly to 
gut region. Aggregate form with testis out- 
side intestinal coil, with short anteriorly up- 
turned endostyle. Aggregate form asymmetric. 
One species, Brooksia rostrata. 
Brooksia rostrata (Traustedt) 1893 
Fig. 9a-e 
Salpa rostrata Traustedt, 1893: 8; Sigl, Y)\2h 
Thompson, 1948). 
Salpa {Brooksia) rostrata Metcalf, 1918: 50; 
Sewell, 1926: 84. 
Brooksia rostrata Ihle, 1935: 527-529; Ihle and 
Ihle-Landenberg, 1935: 24; Thompson, 
1948: 120. 
SOLITARY form: More than 10 specimens 
examined, with length range of 2-31 mm. 
without snout (probable range of 4-62 mm. 
with snout). (Fig. 9b-e.) Test: Flabby, glut- 
inous, without permanent elevations or de- 
pressions; usually absent or fragmentary in 
preserved specimens. Muscles: Six dorsally 
continuous body muscles present; M I-III 
and IV-V-VI-x forming groups dorsally; M 
III-IV touching laterally; a strong longi- 
tudinal muscle coursing on each side of en- 
dostyle from gut to anterior tip of snout (they 
remain separate throughout their length) ; 
these longitudinal muscles joined by M C.^ 
and M I only (this is contrary to Traustedt, 
1893, and Thompson, 1948, but on close 
examination, one can see that no other muscle 
fuses with them as Ihle, 1910, showed). In 
addition to extensions of the ventral longi- 
tudinal muscles, the snout contains two dorsal 
longitudinal muscles that continue with the 
oral retractor. I have thus classified them as 
M bs, or ventral lip sphincter 3. The oral 
retractor is formed by the first dorsal lip 
sphincter (Af) and all three ventral lip sphinc- 
ters. M Bi and C extend to just behind the 
oral retractor. An independent muscle, prob- 
ably formed from M C or Bi (I have labeled 
it C.^), extends ventrally to join the ventral 
longitudinal muscle, as does M I. In one 
specimen, M I is dorsally interrupted, prob- 
ably unnaturally. The horizontal muscle {c) 
is long and relatively narrow. The cloacal 
musculature of Figure 9c, d has been recon- 
structed from fragments. Ciliated groove, gan- 
glion and eye: Ciliated groove long, sinuous 
in large specimens, short and simple in smaller 
ones. The eye has the usual horseshoe shape. 
Ganglion and eye lateral to ciliated groove 
in large specimens, dorsal to it in smaller ones. 
Viscera: Gut somewhat compressed laterally; 
margined by a thin flap of caecum {}) tissue; 
in state E (Ihle and Ihle-Landenberg, 1935). 
The stolon is directed posteriorly. 
AGGREGATE FORM: More than 10 specimens 
examined with length range of 0.8-2. 5 mm. 
(Fig. 9^). Test: Flabby, glutinous, usually ab- 
sent in preserved animals. Muscles: Body mus- 
cles fused dorsally and ventrally into a single 
mass; asymmetric, with two types produced, 
the sinistral and dextral individual, whose 
muscles are mirror images. There are appar- 
ently four body muscles on one side and five 
on the other, but due to the invariably poor 
condition of preserved specimens, muscula- 
ture is difficult to study; consequently, this 
needs further examination. Ciliated groove: 
Simple, anterior to M I. Viscera: Anterior end 
of endostyle widely turned dorsally; endo- 
style short; gut in state A (Ihle, 1937-39); 
