14 'The Hiftory of A N I M A L 8, 
CHITIA 
T H E Chastia is an Infed refembling a hair, or a piece of fine thread: it*s furface 
is fmooch j it’s body rounded, and very (lender in proportion to it’s length; and 
it’s mouth fmall and placed horizontally; the jaws are both of the fame length, and 
obtufe at their extremities. 
Of this genus there is only one known fpecies. 
C H JE T I A, 
%l)t caiiet) atfo 
tije (Sumea-ttojm. 
This Infed, when full grown, is ten or twelve inches, or more, in length, and of 
about the thicknefs of a horfe-hair: it’s fkin is fmooth and fomewhat gloffy, and not at 
all furrowed : it’s colour is a pale yellowifh-white all over, except the head and tail, 
which are black and glofly. 
It is not unfrequent in our frefh waters, and in mod of the other parts of the worldf 
Gefuer calls it Vitulus aquaticus; Merret, Seta aquatica ; Linnteus, Gordius ; and the 
rpedical writers, Dracuncuius, and Vena Medinenfis : our common people call it the 
hair-worm, and imagine it to be an animated horfe-hair. Dr Lifter gives a very par¬ 
ticular account of it’s origin, and fays, that he has found many of them alive, in the 
body of the common black beetle. This is the. worm, that, in Guinea and fome other 
of the hot countries, gets into the flefh of the natives, and occafions great mifchief; 
though authors in general feem not to have found this out: with us, though frequent 
enough in waters where people bathe, it never attempts this. 
ASCARIS. 
^T^HE Afcaris is a fmall Infed of an oblong form, (lender, and covered with a 
very tender and foft fkin : it’s body is of a rounded figure, and is fmaller at the 
ends than in the middle. 
Of this genus there are but two known fpecies; 
Afcaris capite mincre. 
The fmall-headed Afcaris. 
This is a very fmall worm : it’s length is ufualiy about half an inch; it’s thicknefs, 
that of a fmall pin ; it is of a pale red colour, and fmooth furface; and it’s head is fmall 
and (harp, and it’s tail pointed $ it is of a tender fcrudure, and eafily crufhed to pieces 
and deflroyed. 
It is frequent in the mud at the bottom of rivers, and is fometimes found in the 
earth in fpring, but it perifhes there before fummer ; wherever it is found, it is al¬ 
ways in vaft abundance, duffers of millions ufualiy being met with entangled together^ 
It is one of the worms that infefc the inteff ines of the human fpecies, as well as of 
other animals : it’s general place is in the redum, but it has been found in the vagina 
of women who have long laboured under a fluor albus, and of girls in a chlorofis. 
Afcaris capite majore deprejfo. 
The Afcaris 3 with a larger deprejfed head. 
This grows to about two thirds of an inch in length : it’s fkin is foft and tender 3 
it’s colour, a very pale red. It’s head is nearly equal, in diameter, to the thickefl part 
of it’s body 5 but it’s tail is pointed, as in the other fpecies. 
I met with it laid fummer in the mud of Mr Apreece’s fifh-ponds at Wafhingley in 
Huntingdonfhire, and never found it elfewhere. 
LUMBRICUS. 
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