Royal Society. 6i 
face all m angles, the feveral cylinders, to ufe the exprefTion, 
having lome two, ibme three of their fides open to view^ the high 
precipice does alio confift of cylinders, tho' forae are (hotter and 
Ibme longer, by which it may be climbed up as by fo many ftcps ; 
all the ftones on that coaft, whether fingle or in cluflers, or that 
rile up any where out of the land, are all cylinders, tho' of ever 
io different angles ; and there are alio fome four-iquared on the 
fame more. 
Anatomical Ohfervations on the Heads of Fowl 5 hy 2)r. Allen 
Moulen. Phil. Tranf. I>i° 199. p. 711. 
T N the heads of all the fowl Dr. Moulen had the opportunity of 
•*- examining, he conftantly found only one AqudeduSlus, or 
pafTage from the ears to the palate, whereas in men, quadrupeds, 
and lome amphibious fifh, there are always two, one on each fide 
below the entrance of the noftrils into the palate, and opening 
towards the noHrils, for the more convenient reception of air, as 
is fuppofed^ this paffage in fowl is exactly in the middle of the 
palate, below the infertion of the noltrils into it j it is a mem- 
branous tube, capable of admitting a raven's, if not a goofe quill 
in larger fovvl, luch as turkeys, geefe, ^c. and reaches backwards 
as far as the communication from ear to ear, and hence it comes 
to lerve both 5 whereas there is a necefiity of two in thole ani- 
mals, whole ears have no communication ; He conftantly found 
a hollow Ipace, between the two tables of the Os Cuneiforme, 
reaching from ear to ear, and as far forwards as the aforelaid 
common AquteduSius^ or rather, 'DuBus aereiiSy its mechanilrn 
feeming more to favour this than the former ulej this cavity in 
all fowl reaches above the labyrinth us on each fide, fb that what- 
ever impulfe is made on the ^I'ympanum on the one fide, may not 
only be very readily communicated by means of the internal air 
to the LahyrmlJi'.s of the fame, but alfo to that of the oppofite 
fide ; hence probably proceeds the quicknefs of hearing, and the 
vigilancy of fowl, notwithftandingthey want a Cochlea^:, the defeiSl 
of which leems to be by this ftruclure more than iupplied, no 
other animal, as far as is known, having any thing like it 3 it is 
not improbable, that the oppofite ear is altogether as much 
affected by the Ibund, as that next it, if not more ^ there are 
feveral Lamlnulce^ and pillars of hard bone, between the two 
tables in fbeie cavities, defigned, as may be fuppoled, partly for 
keeping them at a convenient diftance, and partly for breaking of 
the air," fo as to hinder echoes and confuled reprefentations of 
objeclj:, as it has been ingenioufly obierved by Sir. J, HoskinSy 
that 
