42 Nils Hj. Odhner. 
The muscular layers are of the usual structure: a circular 
stratum outermost and a longitudinal one internally; between 
them a layer of obliquely crossing fibres. On the ventral side 
the longitudinal musculature is thickened towards the ventral 
furrow, and here the musculature is penetrated by radiating fibres, 
which also extend upwards to the lateral and dorsal sides of the 
body forming very strong septal muscles. 
Between body wall and intestine there is, as usual, a rather 
spacious lacunar system, filled with blood corpuscles. The lacunae 
communicate, through slender canals between the muscles, with 
the ventral sinus, which is divided longitudinally by means of a 
horizontal septum. Above the latter the salivary glands are 
situated immediately beneath the intestine; their walls are thick, 
showing a multicellular layer of secretory cells which empty their 
content into a narrow excentric canal lined with a thinner ciliated 
endothelium and situated at the bottom of a superficial furrow. 
The intestine has its walls constituted by a high secretory 
epithelium well folded allround except in the dorsal wall at the 
ventral side of the gonads. Here, on the other hand, the epithelium 
is formed by cubic ciliated cells which pass, towards the sides, 
into the secretory lining. | 
In the gonads both kinds of sexual products were mature. 
They occupied the usual position relatively to one other and were 
arranged as usual in groups, which were fewer in number than 
the intestinal diverticula and thus not corresponding to the dis- 
sepiments. The median septum is thin, and describes a few folds 
on which the eggs are formed each of a single cell. The septum 
contains a dorsal blood vessel and some lacunae here and there 
in its interior. The gonads extend all along the intestine from 
above the oesophagus to the pericardium, which is greatly 
enlarged. 
At each side of the ventral sinus the pedal glands are situated 
round the base of the septal muscles. Laterally of them the pedal 
nerve cords run inside the ventral musculature. The lateral nerve 
cords, which are of about the same strength, run above the middle 
of each body side inside the muscles. 
Of the ventral folds the median one is covered with ciliated 
epithelium and its centre contains a small mass of spongy tissue. 
The two lateral folds have a lower epithelium covered with a 
cuticula and only a few radiating fibres in their centre. 
