30 Nils Hj. Odhner. 
distinguish the present species from all genera of Solenogastres 
hitherto studied; in the latter character it recalls only Simrothiella. 
The circulatory system. From the heart, which depends from 
the dorsal wall of the pericardium, the anterior aorta issues 
between the two genital ducts and further anteriorly it is situated 
dorsally of the genital gland. The posterior end of the heart is 
divided into a bipartite auricle which receives the blood directly 
from the branchial folds. The venous system is represented by 
a wide ventral vessel immediately beneath the intestine, only 
anteriorly separated from it through the salivary glands. Behind 
them the horizontal septum forming the roof of the vessel is 
closely attached to the intestinal wall. On reaching the posterior 
end of body the ventral blood vessel spreads round the sides of 
the coelomoducts, thus forming there a sinus venosus homologous 
with the one existing for example in the Lamellibranchiata round 
the nephridia. It is not likely that the coelomoducts to any extent 
serve as a nephridium; their secretory function seems exclusively 
to subserve their function as genital ducts. From the sinus named 
a superficial venous lacuna spreads along the cloacal margin, giving 
rise to capillaries entering the gill folds. 
The circumintestinal lacunae at the sides of the body are in 
communication with the sides of the ventral vessel. 
The gills are simple projections from the cloacal wall; they 
consist of an epithelium wrinkled transversally so as to recall a 
small ctenidium, and a spongious tissue within. In their anterior 
margin they contain a capillary communicating with the arterial 
vessels in the cloacal roof. These vessels are joined anteriorly 
to a pair of larger ones at the sides of the rectum, and these 
finally open into the auricles. 
The nervous system. The pedal nerve cords are situated, as 
usual, inside the longitudinal muscle fascicles, and well outside the 
pedal gland. At the posterior end of the body they gradually 
disappear into the inferior wall of the cloaca without joining the 
lateral cords, which alone together form the suprarectal commis- 
sure. The lateral cords are only slightly narrower than the pedal 
ones and run in the upper half of the body height on each side 
of the gonads inside the musculature. 
Glands. Besides the anterior and posterior pedal glands, 
which are of the usual character, there are in the cloaca a num- 
ber of glandular tubes (fig. 43). The latter are in reality nothing 
“te 
