Pelagic Tunica ta — B ary 
105 
TABLE 2 
The Ranges and the Ratios of the Lengths of Body and Tail Recorded for Oikopleura fusiformis 
from Elsewhere in the Pacific Ocean than New Zealand 
LENGTHS 
RATIOS, BODY TO TAIL 
AUTHOR 
Body 
Tail 
LENGTH 
Maximum 
Minimum 
Maximum 
Minimum 
Maximum 
Minimum 
Average 
Thompson 
Russeil and 
1.4 
0.4 
5.0 
2.0 
3.6 
5 
4.3 
Colman 
— 
— 
— 
— 
— 
4 
Essenberg 
1.1 
0.75 
3.8 
3.7 
3.4 
5.1 
4.25 
laterally, but narrows appreciably ventrally. The 
intestine forms a loose dextral coil; the anus is 
usually in a median position, but may be dis- 
placed slightly dorsally and to the right; the 
anus and the coil of the intestine lie between 
M.6 and M.7. The testis is coiled; it commences 
near the ovary, situated posterodorsally to the 
coil of intestine, runs forward to about M.5V4 
on the left side, then loops back and curves be- 
hind and above the intestine, ending towards 
the right side where it is usually slightly en- 
larged. The endostyle runs from M.2p2 to 
M.4p2-434. The nerve ganglion is situated at 
M.31/3. 
PHOROZOOID : Similar to the gonozooid in ap- 
pearance and size ( Fig. 7 ) . It is without gonads 
and possesses a median posteroventral process 
between M.7 and M.8 which receives muscle 
slips from M.7. 
Garstang (1933) suggests that D. valdiviae 
may be a form of D. mirabilis ( Korotneff ) . He 
supports this with argument concerning de- 
velopmental trends in the location of the testis 
and branchial septa relative to muscle bands. 
Fig. 4. Doliolum (Dolioletta) valdiviae, diagram of 
the gonozooid to illustrate the chief diagnostic fea- 
tures. Ml to M8, body muscles. 
He says (p. 204) that "There is ... a possi- 
bility . . . that the 'Specific’ differences in the 
limiting attachments of the gill septum [be- 
tween each of several pairs of species} are ulti- 
mately matters of differential growth rates and 
doubtless modifiable by nutrition, temperature, 
and similar environmental factors, as in other 
cases.” Nevertheless he distinguishes D. valdi- 
viae from D. mirabilis ( = chuni) by the dif- 
ferent positions of attachment of the ventral 
septum and the extension behind M.6 of the 
septum, together with the length of the endo- 
style and the coiling of the testis ( see Garstang, 
p. 216, fig. 5), and the fact that in D. mirabilis 
M.6 is incomplete ventrally, which is "without 
precedent” (p. 221). Sewell (1953: 53) re- 
gards the two gonozooids he collected as com- 
bining certain characters of both D. valdiviae 
and D. mirabilis: "In the length of the endostyle 
and the interrupted Vlth body muscle, they con- 
form to D. mirabilis, but the position and ar- 
rangement of the testis comes more nearly into 
line with the description of D. valdiviae. The 
ending of the gill lamella ventrally at the Vth 
muscle band agrees with D. valdiviae, whereas 
in D. mirabilis it is continued forward to the 
level of the IVth body muscle.” He inclines to 
FIG. 5. Dolioletta valdiviae, gonozooid of 3-9 mm. 
length. 
