318 
PACIFIC SCIENCE, VoL VIII, July, 1954 
cannot be established for it. Stiasny (1926) 
figured and described a longitudinal depres- 
sion midventrally, limited to the anterior part 
of the test. I have not seen such a depression 
on any of my specimens, but in all the smaller 
ones there is a small circular depression for 
an attachment organ, which perhaps is what 
he saw. This is absent in larger specimens. 
The elaeoblast is relatively much larger in 
smaller specimens but is always a much- 
flattened disc. Muscles: Four body muscles; 
M I and II converging dorsally as do M III 
and IV; laterally all muscles diverging from 
one another, thus forming two X-shaped fig- 
ures dorsally; muscles short. Ciliated groove: 
A large vertical loop whose ends approach 
one another anteriorly. Viscera: Gut compact, 
in state H (Ihle and Ihle-Landenberg, 1938^) ; 
elaeoblast forming a disc beneath gut; stolon 
encircling gut closely; endostyle weakly sinu- 
ous; on each side of endostyle at level of gut, 
a row of raised projections which have been 
noticed only by Ihle and Ihle-Landenberg 
(1938^), who described them as 'Taken des 
Pharynxbodens” (/in Fig. 24). (These are 
not present in the aggregate generation.) 
AGGREGATE FORM: More than 10 specimens 
examined with length range of 4-48 mm. 
(Fig. 25). Test: Loose, flabby, thin except 
around gut swelling and occasional thickened 
regions; gut swelling prominent, bearing 
ridges or elevations above and below a cir- 
cular longitudinal depression which is very 
shallow; ventral surface usually with a rather 
thickened narrow elevation; thin membranous 
sheets of test material may extend loosely out 
from gut swelling; in bicaudate specimens, 
two triangular extensions of test containing 
mantle epithelium extending dorsolaterally 
over gut swelling, one to each side of cloacal 
opening; on all specimens, two lateral and 
twd ventral attachment organs on each side 
of body, making a total of eight; attachment 
organs tubular, prominent, symmetrical. Sti- 
asny (1926) figured prominent ridges both 
ventrally and dorsally in addition to the gut 
ridges. My specimens do not agree with this; 
as the test is flabby, presence of depressions 
and elevations is considered here to be a 
matter of chance. The cloacal siphon forms 
a weak flap. Muscles: As in the solitary form, 
M I and 11 form an X-shaped group dorsally, 
as do M III and IV; they extend only to the 
lateral surface. Ciliated groove: Forming a large 
loop whose ends approach anteriorly. Viscera: 
Gut compact, in state C of Ihle and Ihle- 
Landenberg (1933); endostyle sinuous; em- 
bryo on right dorsal region between M III 
and IV. 
The subspecies bicaudata of Metcalf (I9I8) 
is perhaps only a slight modification of 
the typical form. Sewell (1926) stated: "I 
Fig. 24. Pegea confoederata, solitary form, left side. 
