318 DR, A. E. SHIPLEY ON (Mar. 16, 
Nervous System. 
We have not made a detailed examination of the nervous 
system, but may remark that it consists of a brain and a large 
infra-cesophageal ganglion in the head and of three ganglia in 
the thoracic seoments, The last of these is the largest, and 
it supplies nerves to the organs of the abdomen. 
Circulatory System. 
This, again; we have not examined, but Wedl* and Kramer? 
have seen and described the hearts of several species. They 
seem to conform to the usual insect type, but the number of 
chambers is small, Wedl says only one in Menopon pallidum, 
situated in the last but one abdominal segment. 
Reproductive Organs. 
We have not investigated this system of organs in any detail, 
but it may be mentioned that in the Ischnocera, the subdivision 
of the Mallophaga to which Goniodes and Nirmus belong, there 
are four testes, the two on each side being united by a common 
vas deferens, which leads into a vesicula seminalis, which, though 
bilobed, is usually unpaired; from this an ejaculatory duct leads 
to a retractile penis. The extreme complexity of the external 
male organs is shown in fig. 9, Pl. XXXVIIT. Morphologically 
there is an invagination of the body-wall of the last abdominal 
segment to form the genital cavity, and the various plates and 
bars which are seen in the drawing are chitinous thickenings in 
the walls of the invagination. In the centre of the genital 
cavity lies the penis, which is strengthened by chitinous rods and 
bars, and is capable of being protruded and retracted by a com- 
plicated system of muscles. In the male the anus has been 
involved in the invagination and comes to open dorsally into the 
genital cavity. This is not the case in the female, where the 
invagination is not close to the posterior end, but is formed by 
an invagination of the eighth abdominal seoment. The vagina 
opens anteriorly and dorsally into this chamber, and passes into 
a long coiled oviduct which splits into two collecting- ducts, and 
these terminate in five ovaries on each side of the “body. The 
ovaries dwindle out anteriorly, and their thread-like forward 
ends unite into a common termination. 
An excellent comparative account of the reproductive organs 
of the ern is given in Snodgrass’s already-mentioned paper, 
and Gross £ has written an necount of the histology of the ovary, 
which he finds strikingly like that of the Pediculidee. 
* SB. Ak. Wien, xvii. 
+ Zeitschr. wiss. Zool. xix. 1869, p. 452. 
t+ Zool. Jahrb. Anat. xxii. 1905, p. 347. 
