vvhofe eyes are capable of being fet in the manner of 
glaffes and ufed as microfcopcs. This enormous Spi¬ 
der is not uncommon in many parts of America, but 
it is principally found in South-America. It reiides 
amongft trees, and frequently feizes on fmall birds, 
which it deftroys by fucking their blood, alter having 
firfi: wounded them by its fangs, which inftil a poifon- 
ous fluid into the wound, in the manner of other Spi¬ 
ders. The flit or orifice near the tip of the fangs of 
Spiders, through which the poifonous fluid is evacu¬ 
ated, and the exiftence of which has afforded fo much 
matter of doubt amongft Naturalifts, is in this fpecies 
fo vilible that it may be diftindlly perceived without 
a glafs. 
To thofe who are accuftomed to microfcopical in- 
veftigations, and make ufe of the advantageous ftruc- 
ture of the opake microfcope, it may feem furprifing 
that any doubt could ever have been entertained of the 
exiftence of this foramen in the fangs of Spiders, lince 
even in the common Houfe-Spider it is perfectly vifi- 
ble by the afliftance of the firft or fecond magnifier of 
Liberkun’s microfcope; but it fhould be confidered 
that microfcopes of the ufual ftruvfturc arc not calcu¬ 
lated for fhewing to advantage fo fmall an objeeft, and 
which requires fo favourable a light. Even Swam¬ 
merdam and Roefel could not difeover it; and it is 
notorious that Mead in his Account of Poifons, ima- 
. gines Leewenhoek to have been miftaken in fuppofing 
that the Spider evacuated its venom through a hole in 
its fangs; and declares that he himfelf had examined 
the fangs of feveral Spiders, and of this large one in 
, particular, 
