vvhofe eyes are capable of being fet in the manner of 

 glafles and ufed as microfcopes. 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 fmali birds, 

 which it deftroys by fucking their blood, after having 

 firft 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 (pedes 

 fo viiible that it may be diftindtly 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, fince 

 even in the common Houfe-Spider it is perfectly vili- 

 ble by the afliftance of the firft or fecond magnifier of 

 Liberkun's microfcope ; but it fliould be confidered 

 that microfcopes of the ufual ftru&ure are not calcu- 

 lated for fhewing to advantage fo fmall an object, and 

 which requires fo favourable a light. Even Swam- 

 merdam and Roefel could not difcover 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, 



