BLATTA. 229 
three to form the subcesophageal mass, and the fusion of the last five to 
form the terminal abdominal ganglion. As in the lobster, the first two 
ganglia move forwards to the brain and the jaw-ganglia fuse together. 
In the cockroach there is no trace of excretory glands 
opening at the base of any of the -appendages. 
A different kind of excretory organ is found in 
the Alalpighian tubules described above. 
‘The ¢rachee are tubes, lined with chitin, thickened in a 
spiral, and passing inwards from the stigmata. They branch 
all over the body and pass into the wings. They 
appear in dissection like delicate silver tubes. In 
a general way, there pass inwards from each stigma a dorsal, 
a ventral and a splanchnic branch. The dorsal branches 
anastomose beside the heart, the ventral anastomose near 
the nerve-cord, and the splanchnic branch all over the vis- 
cera. The first stigma sends two large paired trachez 
forwards to supply the head. 
The male organs consist of a pair of minute des¢es in the 
dorsal part of the middle of the abdomen. ‘They lead by 
small vasa deferentia into a “ mushroom-shaped 
gland,” a tufted organ which is really a paired 
vesiculum seminalis ; an ejaculatory duct passes from these to 
the exterior. 
In the female each of the paired ovaries consists of eight 
long tubes or ovarioles. They unite to form a pair of 
ovtducts which open together on the 8th sternon. The 
short united portion is sometimes called the uterus. A 
pair of branched colleterial glands open into the uterus and a 
small sac or sfermatheca opens on the gth sternon. In 
both sexes there are gonapophyses or paired sclerites, modi- 
fied to assist reproduction—in the male for copulation, in the 
female for deposition of the ova. In the female the 8th 
and oth sterna are telescoped within the large 7th, 
producing a genital pouch, It should be noted that the 
female opening, as in the lobster, is two segments anterior 
to that of the male. 
The eggs are laid in a capsule (one from each ovariole, making 
sixteen in all) formed by the co/letertal giand;. They have much yolk, 
and the segmentation is equal and superficial. A ventral 
Development. A/afe is produced by a thickening of the cellular layer. 
This is invaginated, the walls meeting above and forming 
an anmion, a remarkable protective membrane, found also in land 
Excretory. 
Respiratory. 
Reproductive. 
