402 A. J. NICHOLSON 
canal, which it enters a short distance anterior to the genital 
aperture. A mucous gland, which consists of very large goblet 
cells, also communicates with the gynaecophorice canal, close 
to the entrance of the sperm-duct (fig. 7). 
The ovary is surrounded by two sheaths, an outer bag-like 
structure, the investing membrane, and an inner membrane, 
which is closely applied to the egg-follicles and fits them like 
a glove; the fingers of the glove are the follicular tubes and the 
portion joining up the fingers encloses the lumen of the ovary. 
The investing membrane passes anteriorly into a tubular 
suspensory filament, which is fixed to the hypodermis at the 
junction of the fourth and fifth segments, i a dorso-lateral 
position. This filament is very long in the young ovary, 
but it becomes quite short when the ovary is fully developed. 
The two sheaths are identical in structure, and consist of 
a structureless membrane, over one surface of which large 
nuclei are found. From these radiating muscle-bands pass 
over the membrane. ‘These nuclei and muscle-bands are on 
the inside of the investing membrane and on the outside of 
the follicular tubes, and muscle-bands pass from the nuclei 
of the one to the other, thus traversing the cavity between 
the two sheaths and linking the investing membrane and the 
folhcular tubes together, so forming a very complicated 
muscular system (fig. 24). 
The muscle-bands of the sheaths are striped in the normal 
manner, thus differmg from those of most insect ovaries (see 
J. Gross, 9). They form broad bands close to the point of 
origin from the nuclei and taper away from here and branch, 
some of the finer branches appearing to consist of only a few, 
or even a single muscle-fibre, as the ‘striations’ consist of 
bead-like, deeply-staining nodes on a fine thread (fig. 24). 
It would probably be more correct, in many cases, to consider 
that the nuelei are placed at intervals on the muscele-fibres, 
rather than that they are the origin of the fibres. From an 
examination of fig. 28 it will be seen that many muscle-bands 
pass through the cytoplasm of the cells, and merely become 
slightly indefinite there. The ‘striations’, though somewhat 
