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PACIFIC SCIENCE, Vol. VIII, July, 1954 
swinging outward at level of gut swelling and 
inward toward anterior third of body; cloacal 
flap of two fused halves, fringed as in Thalia 
democratica; transverse groove anteriorly at 
base of flap, posteriorly around cloacal open- 
ing. Muscles: M C and the five body muscles 
are broad; all muscles interrupted dorsally and 
ventrally; M V relatively narrow, extending 
only a short distance toward ventral surface. 
Ciliated groove , ganglion and eye: Ciliated groove 
simple, straight, located between the two bow 
muscles; ganglion and eye between M C and 
M I; eye may be transversely elongate (Fig. 
l)Od). Viscera: Gut in condition D of Ihle and 
Ihle-Landenberg (1933) ; stolon forming circle 
around gut, opening to outside of test by 
means of a posterior opening just above gut 
(small in Fig. 30^ but may be much larger). 
AGGREGATE FORM: More than 10 specimens 
examined with length range of 19-37 mm. 
(Fig. 30/-/). Test: Asymmetric; consistency 
as in solitary form; dorsal depression (raised 
in cross section) with deep groove on each 
side but without fine median ridge described 
by Stiasny (1926), extending to base of upper 
lip; dorsal limiting elevations may bear a weak 
ridge on each side of depression; anteriorly 
both lips project dorsally prominently; a 
prominent chin forming anterior to lower lip; 
laterally a deep lateral groove (often a broad 
depression) extending from region of cloacal 
flap to level of mouth (weak ridges may 
course above and below this); lips and chin 
prominent in lateral view; ventrolateral ele- 
vation extending posteriorly as a ridge onto 
posterior projection; gut swelling prominent; 
on ventral surface, a broad, raised in cross 
section, midventral depression with a deep 
groove on each side, extending to chin; lim- 
ited by ventrolateral elevations; rear projec- 
tion always on right side, usually long but 
may be short; a broad, long mantle process 
extending into posterior projection; attach- 
ment organs prominent; two anteriorly di- 
rected, one ventrally directed on chin; two 
midventral, raised on an elevation; three pos- 
terior, raised on an elevation of gut swelling. 
The number described is the maximum num- 
ber as reported by Streiff (1908) and Stiasny 
(1926). Some individuals may deviate from 
this maximum (Fig. 30g). Further, Stiasny 
shows two prominent lateral ridges rather than 
a single lateral groove. He also shows prom- 
inent dorsal ridges ("Crista”) which are usu- 
ally only rounded elevations on the specimens 
examined here, but in general his description 
is applicable. Muscles: Five body muscles (M 
C is not shown in figure) ; all interrupted ven- 
trally, M I interrupted dorsally as well; M V 
dividing into two branches on right side, 
remaining single on left. Ciliated groove: Sim- 
ple, anterior to M I. Viscera: Gut compact, 
in condition F of Ihle and Ihle-Landenberg 
(1933); testis projecting as lobules around 
gut; up to five embryos present dorsally on 
right between M IV and V. 
This species is morphologically one of the 
best-known salps as its test has a different 
refractive index than water, even though it is 
transparent. The test has been figured well 
by Brooks (1893) and Stiasny (1926) and 
described in detail by Stiasny. 
REFERENCES 
References indicated by an asterisk (*) have 
not been seen by the writer. 
*Apstein, C. 1894^/. Die Salpen der Berliner 
zoologischen Sammlung. Arch. f. Natur- 
gesch. 60(1): 41-54. 
1894 A Die Thaliacea der Plankton- 
Expedition. B. Vertheilung der Salpen. 
Ergeb. der Plankton-Exped. 2(E.a.B.): 1-68. 
* 1901. Salpidae (Salpen). In Nord- 
isches Plankton 1(3): 5-10. 
1904. Salpes d’Amboine. Rev. Suisse 
de ZooL 12: 649-56. 
— 1906^. Salpen der deutschen Tiefsee- 
Expedition. Wiss. Ergeb. der Deut. Tiefsee 
Exped. 1898-99 12(3): 245-90. 
1906^. Die Salpen der deutschen 
Siidpolar-Expedition. Ergeb. der Deut. Sud- 
polar-Exped. 1901-1903 9(Zool. 1): 155- 
203. 
