Pacific Salpidae — YoUNT 
281 
Muscles arranged in groups of 4 and 2, 
4 only or 2 only dorsally 18 
16(15). Gut within a broad pointed or round- 
ed median posterior projection; ciliated 
groove bears a ventral languet 17 
Posterior projection not containing gut; 
ciliated groove without languet 
Weelia cylindrica 
17(16). M III is formed of 8 or 9 fibers 
(Apstein, 1906^) . . Thalia longicauda 
M III is formed of 3 fibers (Apstein, 
1906^) Thalia democratica 
18(15). M II extends beyond endostyle to 
between M V-VI of opposite side 
Ihlea punctata 
Mil not as above 19 
19(18). Posterior projection extends beyond 
cloacal opening. 20 
Posterior projection does not extend be- 
yond cloacal opening 
Metcalfina hexagona 
20(19). Independent muscle small, incon- 
spicuous; M I-II narrowly fused dor- 
sally; spaces between transverse ribs of 
gill bar less than 0.5 width of bar 
Salpa maxima 
Independent muscle large, conspicuous; 
M I-II widely fused dorsally; spaces 
between transverse ribs of gill bar greater 
than 0.5 width of bar 21 
21(20). Dorsal lip sphincter 1 (M Ai) in- 
terrupted middorsally 
Ritteriella picteti 
Dorsal lip sphincter 1 continuous mid- 
dorsally Ritteriella amboinensis 
22(1). Intestine accompanies gill bar. . . .23 
Intestine does not accompany gill bar 
28 
23(22). Ventral longitudinal muscle present 
24 
Ventral longitudinal muscle absent. .25 
24(23). A single dorsal longitudinal muscle 
present, connecting M I with M x on 
each side Helicosalpa komaii 
Two dorsal longitudinal muscles pres- 
ent, connecting M I with M VI on each 
side Helicosalpa virgula 
25(23). M I-IV fused ventrally into a single 
mass Cyclosalpa floridana 
M I-IV not fused ventrally 26 
26(25). Three to five light organs present on 
each side of body 27 
Not more than one light organ present 
on each side of body . Cyclosalpa affinis 
27(26). M VI forming 2 anteriorly directed 
dorsal longitudinal muscles 
Cyclosalpa bakeri 
M VI forming one fused, anteriorly di- 
rected dorsal longitudinal muscle, or 
none Cyclosalpa pinnata 
28(22). A muscular snout projects anteriorly 
beyond mouth opening 
. Brooksia rostrata 
No muscular snout projects anteriorly 
29 
29(28). Body muscles interrupted dorsally 
30 
Body muscles continuous dorsally. .31 
30(29). A long projection extending poste- 
riorly from both posterolateral angles of 
body; test spiny Thetys vagina 
No such projections present; test smooth 
lasis 2 onaria 
31(29). Some body muscles form complete 
rings 32 
All body muscles interrupted ventrally 
36 
32(31). Longitudinal muscles present on 
each side of body, internal to body 
muscles Ihlea punctata 
Longitudinal muscles absent 33 
33(32). A long projection extending poste- 
riorly from each posterolateral surface of 
body 34 
No such projections present 35 
34(33). M I-III and IV-V forming groups 
dorsally Thalia democratica 
