Pacific Thaliacea — Tokioka and Berner 
tion slightly behind the cardiac end of the 
stomach. The hind stomach is distinct and 
there is an obvious constriction between it 
and the following portions of the gut. 
The ovary (ov.) is located near the middle 
of the fifth intermuscular zone or slightly 
posterior to it. The testis (t.) is a fusiform- 
shaped stumpy mass, oriented anteroposteri- 
orly, and extending from the ovary to near 
the middle of the fourth intermuscular zone. 
The heart is located near the ovary. 
The phorozooid is similar in appearance to 
the gonozooid, though the corpuscular ag- 
gregation over the area of the gut tends to be 
reduced in the phorozooid. Both the ventral 
ends of muscle VII extend into the ventral 
protuberance (Fig. ID). 
At a glance this new species closely resem- 
bles D. mulleri (Krohn 1852). It differs from 
the latter by having the ventral interruption 
of muscle VII and in the anterior-posterior 
position of the testis. In D. mulleri the testis is 
situated somewhat dorsoventrally and muscle 
VII forms a complete loop. The sigmoid 
curve of the gill resembles D. sigmoides Gar- 
stang 1933 ( = Doliolum krohni Neumann 
1906). The new species completely lacks the 
epidermal tentaclelike processes characteristic 
of D. sigmoides. Interrupted muscle VII is 
another differentiating characteristic. The new 
species differs from D. undulata in the shape 
of the stomach and in the shape and location 
of the testis. In addition, the aggregation of 
corpuscles around the alimentary organs and 
the gonads is unique. The species name 
comes from this aggregation which makes 
these organs obscure. 
The specimens upon which this description 
is in part based are deposited in the U.S. Na- 
tional Museum under the following numbers: 
holotype: U.S.N.M. no. 11371, Doliolina 
obscura , gonozooid, 1 specimen from Shell- 
back station 137 located at 13° 43.5' S. 81° 
08.5' W. 
PARATYPES: U.S.N.M. no. 11372, gonozoo- 
ids, 10 specimens, Doliolina obscura from 
Shellback station 137. 
319 
From the MLR material one aberrant form 
was taken in which the fifth body muscle was 
interrupted and the left limb of that muscle 
extended back to connect with muscle VI. In 
other respects this specimen did not differ 
from the species. The muscle arrangement is 
shown in Figure IE. 
Doliolina separata new species 
Fig. 2 
A few specimens of this diminutive doliolid 
were found in the samples from Shellback 
stations 137, 145, and 180. Most of them 
were poorly preserved and immature, but 
three mature, fairly well-preserved specimens 
were found at station 137. The following de- 
scription is based on these three specimens. 
The specimens were 1.5, 1.7, and 1.7 mm. 
long. The body is somewhat elongate. The 
test is of moderate thickness and is easily 
stripped from the body. Under the micro- 
scope many minute cells can be observed on 
the surface of the test. 
Body muscles I, VII, and VIII are very nar- 
row. Muscle II is somewhat narrower than 
muscles III-VI. Muscle VII is clearly inter- 
rupted at the mid-ventral line. The first and 
seventh intermuscular zones are narrower than 
the others. 
The endostyle (ed.) is very long, extending 
from the posterior margin of muscle II to 
near the anterior margin of muscle V. The 
anterior border of the peripharyngeal band 
(pM I closely approaches muscle I. The cili- 
ated groove (c.g.) is situated approximately in 
the middle of the second intermuscular zone. 
The dorsal ganglion (d.g.) is located in the 
third intermuscular zone near the posterior 
margin of muscle III. The gill septum (g.) 
extends from muscle VI dorsally to muscle V 
ventrally, and bears 10 pairs of somewhat 
elongate stigmata. 
The oesophageal opening is located at the 
center of the circle formed by muscle VI. The 
whole alimentary canal forms an S-shaped 
loop towards the anteroventral side, in the 
