29 
1907-8.] Notes on some Turbellaria from Scottish Lochs. 
retractor muscles ; behind this lies the brain, on the dorsal surface of which 
are placed the two eyes. 
The mouth lies on the ventral surface, at about one-third of the length 
of the animal from the anterior end. 
The pharynx rosulatus in young forms leads into a sac-like gut, which 
occupies most of the body, but in the sexually mature forms, as in Gyrator 
notojps, the gut breaks down to form a loose packing around the gonads. 
In the form examined by Bresslau no such degeneration of the gut was 
found. 
The common sexual aperture lies a little more than half way down the 
body, and near the posterior end is the aperture of a contractile bladder 
into which the paired water-vascular ducts open. 
The proboscis, pharynx, gut, and brain do not offer any features of 
particular interest, but it is necessary to describe in some detail the gonads 
and water-vascular system, as in these organs I find that my account differs 
rather materially from that of Bresslau. The testes are more or less oval 
bodies lying dorsal to the uterus ; they pass into short vasa def erentia, which 
unite and open into a common reservoir which lies close to the secrete 
reservoir, a little to the right and anteriorly of the common genital aperture 
(PL III. fig. 4). 
The duct from the secrete reservoir passes through a short covered 
chitinous tube before joining the sperm duct, and opening into genital 
atrium (PI. IV. figs. 1-2). 
The female genital apparatus consists of paired ovaries (PI. III. fig. 2) 
lying on either side of the genital aperture. The ovaries open into a duct 
which passes forward, receiving the opening of the uterus and the ductus 
seminalis, to the common genital aperture. I cannot find a distinct bursa 
seminalis in the position figured in Bresslau ’s diagram, in which also the 
entire male apparatus is placed on the animal’s left side. 
The cocoon (IV. 5) is a brown oval structure, concavo-convex in 
transverse section, and ending at one pole in a drop of viscid substance. 
Each cocoon contains a single embryo. The yolk glands are bilaterally 
arranged, irregularly branched structures, each gland consisting of two long 
anterior branches and two long and one short posterior branch, which unite 
about half way down the body into a common transverse duct opening near 
the base of the uterus. 
The reserve stuff in the yolk gland appears to consist mainly of fat, 
which blackens readily in osmic preparations. 
Apparently this substance undergoes some chemical change, as the 
cocoon does not appear to contain so much fat. 
