Habits and structure of Cotylaspis insignis Lrıpy. 993 
cirrus sack on the right side and the metraterm on the left. There 
is a penis probably eversible, and a distinct cirrus sack, a seminal 
vesicle external to the cirrus sack running under the intestine to 
the left side where it extends to near the centre of the body, a 
very slender spermatic duct on its inner side crossing under the 
intestine to the other side where it enters the single large globular 
testis, near the hind end of the body. The female system presents 
a uterus of moderate length, distended at intervals by the few 
large eggs, no shell glands, seminal receptacle or LAURER’S canal, 
yolk receptacle and few somewhat large yolk follicles, a peculiar 
oviduct, “fallopian tube” and small oval ovary, on the right side 
and beneath the diaphragm. A detailed account of these part now 
follows. 
II) The male organs. 
The spermary is single as in Aspidogaster and Macraspis, there 
are two in Cotylogaster and Stichocotyle. It is located directly above 
the ventral body wall, and under the hind end of the intestine. It 
is approximately spherical with a diameter ef 0.18—0.26 mm. The 
organ has a distinct wall, with scattered flattened nuclei and 
muscular fibres. The muscles are very scanty unlike Aspidogaster 
where Srarrorp finds a longitudinal and a circular layer. The 
interior of the spermary contains two kinds of cells: the parietal 
cells (Fig. 39) in contact with the wall, and the central cells which 
occupy the interior and are derived from the parietal cells. The 
cells differ markedly in May “resting organ” and in July „active 
organ” the latter showing evidences of spermatogenesis. In the 
resting spermary the parietal cells (Fig. 39) are small, have a very 
small amount of cytoplasm, the nucleus has a very faint membrane, 
no chromatine and a very distinct excentrically located nucleolus. 
The central cells at this time (Fig. 39) are not clustered as in the 
active organ, and each cell is evidently inactive. There is a con- 
siderable amount of cytoplasm, the nucleus has the same size as the 
wall cells, its very faint membrane is only visible by most careful 
illumination. Fine grains apparently of chromatine occur on the 
membrane. The nucleolus is wanting. A section of the active 
Spermary is shown in Fig. 38. The parietal cells (Fig. 41) are now 
quite different, the nucleus now easily seen and deeply stained, contains 
a chromatine net-work; a deeply stained grain in the cytoplasm 
bears much likeness to a centrosome. 
