INTERNAL GENERATIVE ORGANS OF THE FEMALE. 671 
In most insects in which the egg-tubes are numerous, the 
ovarian stroma and capsule present similar characters. 
In the Blow-fly the peritoneal tissue (Fig. 93) which forms 
the stroma and capsule of the ovary consists of adenoid tissue 
similar to that which invests the other organs, but denser and 
permeated by muscle-fibres which diverge in a stellate manner 
from large cells, the processes of which are clearly differentiated 
into muscle-fibres. A similar condition is described by Graber 
in the pericardial septum of the larva of Phryganea striata 
[318, Pl. IX., Fig. 13]. In the septa which separate the ege- 
tubes numerous muscle-fibres extend from the concave to the 
convex surface of the ovary. In the young ovary these septa 
are seen to be the walls of distinct blood sinuses filled with 
pseudo-yelk ; so that, if they are not to be regarded as peri- 
toneal tissue, it would be better not to use the term for any of 
the tissues of an Arthropod. 
The Oviducts commence by wide-open trumpets which are 
attached to the capsule of the ovary and open freely into its 
cavity. They are directed forwards, and unite beneath the 
ovaries in the middle line to form the azygos oviduct. This 
curves upon itself and opens into the utero-vaginal tube on the 
dorsal aspect of the latter. The oviducts are very muscular, 
exceedingly distensile tubes ; in the empty condition their walls 
are strongly plicated. There are two dilatations at the terminal 
extremity of the azygos oviduct, immediately before it joins 
the utero-vaginal tube. The anterior of these is similar in 
structure to the oviduct itself. I term it the sinus of the 
oviduct. The more posterior, unlike the oviduct proper, is 
lined by a plicated cuticular layer. I term it the sacculus. 
The oviduct consists externally of a peritoneal layer con- 
tinuous with the capsule of the ovary; beneath this there is a 
thick muscular coat, consisting of two layers of striated muscle- 
fibres, an external longitudinal and an internal circular layer. 
The tube is lined by large cubical epithelial cells, which in the 
distended oviduct are flattened out into a pavement layer. 
In the contracted state the trumpet-shaped tuba measure 
about ‘75 mm. in length, and have a diameter of *5 mm. in 
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