[ 3 °] 
enough found •, but the greateft Difficulty lies in dif- 
covering the other two Pair, which are fmall, and- 
lie envelop’d in diftind little Bags, or a fine fort of 
Membrane. Thefe he takes to be the Auditory Or- 
gans, and anfwer to the Incus , Malleus , and St apes , 
in other Animals: And he thinks by a diligent and 
careful Infpedion, we might determine the Age of 
Fifhcs, by the Number and Thicknefs of the La- 
mina and Fibres of thefe Bones, as we can the .Age 
or Growth of a Tree, by the Number of Circles in 
the woody Part of its Trunk. 
The Paflages by which a tremulous Motion pro- 
ducing the Senfe of Hearing, may arrive at thefe 
Auditory Organs, are what our Author next inquires 
after 5 and he produces firfi: a Specimen in the Spi- 
nofe Kind, viz . in a Jack or F ike ; and upon In- 
fpedion into the Head of this Fiffi, he obferves fe- 
veral Holes, which, by means of Hogs Briftles, he 
finds lead diredly to thefe Auditory Bones before 
deferib’d. 
In differing the Head of a Sturgeon , (as a Speci- 
men of the Cartilaginous Kind) he traced the Audi- 
tory Dud as far as the Membranous Body in which 
the three Pair of little Bones are placed. 
But as our curious Author has obliged us with an 
exad Delineation of thefe Auditory Duds or Paf- 
fages, as well as the Figures of a Variety of thofe 
Lapilli or OJJicula , from different forts of Fifii, on 
feveral Copper Plates, to thefe I muft refer, for a 
more fatisfadory Idea than can poilibly be given in 
Words. 
We therefore proceed to the firfi Appendix, which 
entertains us with the Anatomy of a Forpefs. This 
Fifh 
