306 Chonicles of Scrence. [ April, 
with a pair of four-jointed palpi, but according to Landois, exhibit- 
ing a bifid labrum armed with hooks at one extremity, and reach- 
ing with the other far back into the head ; (2)a pair of mandibles 
underneath the haustellum. This type of mouth differs funda- 
mentally from that of all known arthropods; moreover, the so-called 
mandibles are totally devoid of muscles, and the pointed narrow form 
of the head in the louse is not such as to give support to biting organs. 
Professor Schjédte objects altogether to the mode of examination 
—that of cutting off the head and squeezing it flat on glass,—by 
which Landois and others have made their observations ; for when the 
head is examined from beneath by reflected light without pressure, 
the so-called mandibles are seen to be within the skin, and, therefore 
certainly are not mandibles. He then describes how he observed the 
little lice, as did old Swammerdam, by letting them quietly feed on 
his own hand after keeping them hungry for a day or two, pro- 
truding their haustella, and sucking vigorously at the blood, while 
a pumping action was visible in the esophagus, and the mtestines 
worked with a regular peristaltic action. Lice are, according to 
our author, to be considered merely as bugs, modified to suit their 
position in life, their mouth being of the true Rhyncote type. 
Swammerdam, who wrote more than a century since, appears to 
have been almost exact in his description, and observed the small 
pumping ventricle at the base of the haustellum, which Schjodte 
again describes, whilst, with evident enthusiasm, he commends the 
writings of Swammerdam to his readers’ study. 
The microscopic examination of the fibres of meat cut from animals 
which had died of the cattle plague, has brought an interesting 
parasitic structure again before the notice of naturalists. In the 
ultimate fibres of the muscles of such animals, and also more rarely 
in healthy individuals, exceedingly minute, elongated, saccular 
bodies with granular contents, and a finely fringed envelope, are 
to be observed ; and there has been much question as to whether 
these are entophytes or entozoa, or anything else. Meisner appears 
to have first described such bodies in 1839, having observed them 
in the muscles of a mouse. The best account of them, however, is 
that of Raimey, in the ‘ Philosophical Transactions of 1857,’ who, 
though he mistook them for the young forms of cestoid entozoa, 
described them very accurately, and observed that they gave rise to 
smaller ovoid bodies, which he carefully figures. These observa- 
tions were made in the pig. There can be little doubt that the 
parasites are Gregarinz, and that the smaller ovoid bodies are their 
“psorosperms” or “ pseudo-navicells,” though Dr. Beale and Dr. 
Spencer Cobbold; who have lately been examining those from the 
cattle-plague meat, do not give a definite opinion. The most 
unpleasant part of the matter is, that we are all probably frequently 
eating these minute parasites without being aware of it; and may, ~ 
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