280 
PACIFIC SCIENCE, VoL VIII, July, 1954 
Fig. 2. Schematic median section of a solitary salp 
(after Ihle, 1935). A, Velum muscle; an, anus; B, lip 
muscle; bl, blind sac (caecum of gut); BM, body 
muscles; C, bow (intermediate) muscle; eg, ciliated 
groove (dorsal tubercle); cl, cloaca and its opening; 
e, eye; el, elaeoblast; end, endostyle; g, gut (intestine); 
gb, gill bar; gn, ganglion; h, heart; m, mouth; oe, 
esophagus; ph, pharynx; pi, placenta; pp, peripharyn- 
geal band; st, stolon; x, first cloacal muscle; y, second 
cloacal muscle; z, third cloacal muscle (composed of 
a series of small sphincters). 
KEY TO WORLD SPECIES AND REPRODUCTIVE 
FORMS OF SALPIDAE 
1. Gonads present; stolon absent; eggs or 
embryos usually present aggregate 
(gregarious) form 2 
Gonads absent; stolon usually present; 
eggs and embryos absent solitary 
(oozooid, asexual) form 22 
2(1). Intestine straight, anteriorly directed; 
one light organ present laterally between 
M II-III (there may be another between 
M III-IV) Cyclosalpa pinnata 
Intestine neither straight nor anteriorly 
directed; no light organ present. ..... 3 
3(2). Two posterior projections present, 
containing testis and a caecum, respec- 
tively Cyclosalpa bakeri 
One or no posterior projection present . 4 
4(3). Testis spherical . Helicosalpa komaii 
Testis not spherical 5 
5 (4). Posterior appendage containing testis 
present 6 
Posterior appendage containing testis 
not present 7 
6(5). Testis projects dorsolaterally within 
posterior test projection ............. 
Helicosalpa virgula 
Testis projects ventroposteriorly within 
posterior swelling 
. Cyclosalpa floridana 
7(5). Gut forms a broad loop with central 
space empty; a peduncle present 
Cyclosalpa affinis 
Gut either tightly looped or with central 
space filled; peduncle absent 8 
8(7). Some body muscles form complete 
rings 9 
No body muscles form complete rings 
10 
9(8). Body muscles fused into a single unit 
dorsally and ventrally 
Brooksia rostrata 
Body muscles not fused into a single 
dorsal and ventral unit; however, M II 
and III are rings. . .Ihlea magalhanica 
10(8). All body muscles interrupted dorsally 
Thetys vagina 
Some or all body muscles continuous 
dorsally 11 
11(10). M I interrupted dorsally 
lasis zonaria 
M I continuous dorsally 12 
12(11). Four symmetrical attachment organs 
project from each side of body 
Pegea confoederata 
Attachment organs either asymmetrical 
or not projecting beyond test outline . 1 3 
13(12). One elongate tentacle projects pos- 
teriorly from each lateroposterior angle 
of body . Traustedtia multitentaculata 
No elongate tentacle as above (short 
attachment organs may project laterally 
from the posterior region of Thalia dem- 
ocratica agg.) 14 
14(13). Ventral lip sphincter 4(Mb3) inter- 
rupted Salpa fusiformis 
Ventral lip sphincter 4 continuous, if 
present 15 
15(14). Muscles arranged in groups of 3 and 
2 dorsally .16 
