100 F. G. HEATHOOTE. 
numerous in the male, but this may possibly be due to 
individual differences. I have not had a sufficient quantity 
of males to make certain. 
The Malpighian Tubes. 
Bode succeeded in dissecting out the Malpighian tubes, but 
their minute structure has never been described, and as they 
show a variation from the ordinary form of these organs which 
is not found in any other Myriapod, it is worth while to give a 
short account of them. 
Each tube—there are a pair of them—leaves the junction of 
the rectum and mid-gut as a stout tube with a definite lumen. 
The lumen is surrounded by a ring of denser tissue which 
has a faintly striated appearance. Each tube passes backwards 
along the rectum to the terminal dilation of the latter where it 
becomes greatly thickened, and is doubled upon itself so as to 
form a great spherical knot, the greater part of which hes in 
the semicircular chitinous elevations which are placed at 
either side of the anus. From this coil each tube passes off 
greatly reduced in size so as to have the form of a thin tube 
(figs. 8, 9, 6, 7. malp. t.) like any other Malpighian tube. 
These two thin returning portions pass forward and end 
blindly about the middle of the body. From the anterior end 
of the rectum, where the Malpighian tubes originate, the whole 
of these structures, together with the rectum, is enveloped in 
a membrane (figs 6, 8, 9) which passes’ backwards and becomes 
fused with the mass of cells forming the hypodermis. This 
membrane is perfectly definite on the external surface of the 
Malpighian tubes, but I have been quite unable to find any 
trace of it between the tubes and the rectum. I am con- 
vinced that it envelopes the tubes and the rectum together. 
Where the small returning portions of the Malpighian tubes 
pass beyond the origin of the tubes and the enveloping mem- 
brane, at the anterior end of the rectum, they pierce the 
membrane, and passing forward lie close to the mid-gut just 
like other Malpighian tubes. 
The salivary glands, which are long and tubular, open on 
