Pacific Salpidae- — YoUNT 
325 
AGGREGATE FORM: More than 10 specimens 
examined with length range of 1-12 mm. 
(Fig. 29). Tes^' The echinate form (Fig. 29^) 
is discussed first. Test asymmetric, thick, 
stiff, with prominent, sparsely spiniferous 
ridges and with deep grooves and depressions; 
middorsal depression (limited to anterior re- 
gion in some specimens) limited by spinifer- 
ous dorsal limiting ridges; depression con- 
stricted at base of dorsal lip, widening ante- 
riorly around mouth; a transverse ridge in 
front of cloacal flap; cloacal flap hemispherical 
rather than triangular, fringed as in solitary 
form; gut swelling projecting in a point to- 
ward rear (this may be very long in young 
specimens as figured by Apstein, 1906^^, Se- 
well, 1926 , and Tokioka, 1937), bearing five 
spiniferous ridges that are usually symme- 
trically arranged; lateral ridges asymmetric, 
spiniferous; anterior end almost truncate; ven- 
trally a single deep groove in a broad depres- 
sion cut off anterolaterally by an oblique 
spiniferous ridge that connects with anterior 
end; gut swelling with a strong ventral ridge; 
attachment organs varying in number, elon- 
gate and filiform (but usually not projecting 
beyond test margin) . There is a great amount 
of test variation as reported by Stiasny (1926). 
In the smooth form (Fig. 29^), test flabby, 
without spines of any kind, with long attach- 
ment organs usually projecting beyond test 
outline; no permanent ridges or grooves, but 
there may be depressions and elevations; pro- 
truding gut swelling; cloacal flap with fringes. 
Muscles: Five body muscles; M V relatively 
narrow; all muscles continuous dorsally, in- 
terrupted ventrally; M I-III in contact dors- 
ally, forming a group as do IV and V. 
Ciliated groove: Far anterior; simple, with a 
languet projecting into pharynx. Viscera: Gut 
compact, in condition B (Ihle and Ihle- 
Landenberg, 1933); elongate; protruding far 
into gut swelling; endostyle short, extending 
anterior to level of M I or II only; embryo 
far behind M IV on right ventral body wall. 
The variety orientalis recognized by Tokioka 
( 1937 ) is based on the following differences: 
Fig. 29. Thalia democratica, aggregate form, a, Echin- 
ate form, dorsal surface; b, same specimen, test, ventral 
surface; c, same specimen, test, right side; d, same 
specimen, schematic cross section of test at level of 
M III; e, smooth form, right side, slightly dorsal; 
/, scheme of cross section of test at gut swelling of 
specimen in a. 
