9 
of the muscular wall of the body, the entrance to the pocket 
becomes quite long without causing a ridge to appear in the 
pharyngeal cavity. 
The pharynx has numerous thick and very muscular folds, and its 
structure seems to indicate that it can be protruded to a great 
length. It is apparently adapted for a more efficient gathering of 
the food. The organization of the main gut clearly shows that 
only smaller organisms or small food parts can enter the internal 
mouth, which is situated near the frontal end of the pharyngeal 
pocket. The main gut is only a very siender tube, which in dia¬ 
meter is hardly more than Vio of the width of the pharyngeal pocket. 
In spite of the great length of the main gut, only a few roots of 
intestinal caeca branch off, having at their bases a very small dia¬ 
meter. Two pairs occur in the region of the mouth, and one 
further pair is close to the interior mouth. Numerous but very 
insignificant lateral projections of the main gut, however, exist. 
The more peripheral canal-system becomes, nevertheless, quite ex- 
tensive. Mi not’s granular cells („K6rner-kolben“) are numerous 
in the main gut, but only a few are found in the gut-diverticula. 
The secretion corpuscles, which are decidedly eosinophile, are of 
uniform and very small size. 
Genital organs. 
The testes are very numerous and are densely clustered. Although 
they are situated on the ventral side, they almost reach the mid- 
region, and hence project in between the intestinal branches. This 
deviation from the normal in Polyclads is not only due to the 
above-mentioned thickness of the ventral muscular wall, but also to 
the faet that the ventral net-work of nerves above the ventral mus¬ 
cular layers becomes so well-developed that the larger nerve-trunks 
compete in size with the thick inner longitudinal muscular layer. 
The ovaries are less numerous than the testes. They are oval 
in shape, and, extending in a dorso-ventral direction, project in 
between the intestinal caeca. This is especially apparent in the case of 
the larger and more mature ovaries. The smaller ovaries, in which the 
oocytes are still insignificant, lie in the dorsal half of the body, 
close to the inner side of the muscular body-wall, while the larger 
