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PACIFIC SCIENCE, Vol. XII, October, 1958 
Fig. 6. A, Cyclosalpa strongylenteron Berner 1955, visceral region of the aggregate form, sinistral individual, from 
the right side. B, Same for dextral individual. 
Abbreviations: an., anus; d.c.g., duct of the circum-intestinal gland; ed., endostyle; em., embryo; g., gill; ht., 
heart; int., intestine; l.c., left blind sac; l.o., luminous organ; l.x., left dorsal visceral muscle; l.x'., left ventral 
visceral muscle; oe., oesophagus; r.c., right blind sac; r.x., right dorsal visceral muscle; r.x'., right ventral visceral 
muscle; t., testis; v.d., vas deferens. 
crosses the duct of the circum-intestinal gland 
on the left side, and extends to near the base 
of the testis. The right visceral muscle (r.x/) 
extends along the left side of the left caecum 
to a point near its posterobasal portion. 
In the sinistral individuals the small right 
caecum is completely missing. The left cae- 
cum turns across the alimentary tract on the 
right side as shown in Figure 6A. The duct of 
the circum-intestinal gland opens at the base 
of the left caecum. Other structures are the 
same as in the dextral individuals. 
The asymmetries found in the relation be- 
tween the large (left) caecum and the small, 
or absent, right caecum, the arrangement of 
the testis, vas deferens, duct of the circum- 
intestinal gland and the visceral muscles, are 
all of a primary character. The twist of the 
left caecum, shown in the sinistral individ- 
uals, may be considered to have been brought 
about by enatiomorphism. 
The structure of the intestinal loop of the 
aggregate form of Cyclosalpa bakeri Ritter 1905 
(Fig. 8) closely resembles that of the aggre- 
gate form of C. strongylenteron. It is U-shaped, 
with the anus (an.) opening on the same level 
as the oesophageal opening (oe. op.). The 
right caecum is absent in both the dextral and 
the sinistral individuals. In the dextral indi- 
viduals the left caecum (l.c.) is attached ven- 
