Note on Heteronomic Isomorphism. 407 
nothing regular about them, no subjection tolaw. The young 
animal itself regulates and controls them. There are vibratory 
cilia, that is to say, organs of locomotion, and where these do 
not exist, vibratory cells. There is not an external force under 
the dominion of which it is caused to move. 
The egg possesses organic life from the moment when it ap- 
pears under any form whatever, therefore it cannot be said to ac- 
quire it when it begins to move. Besides eggs, as eggs, move not ; 
when: they move they are no longer eggs; they are embryos. 
For when movement occurs it does not take place till after the 
division of the yolk; and after that division, the embryo exists. 
So that in this view also, the comparison is false. 
Arr. XL..— Note on Heteronomic Isomorphism ; by J. D. Dans. 
Iy the table on page 241, of this volume, the mineral Petalite 
is placed with the triclinic feldspars. ‘The cleavages appear to 
as how understood, not wholly analogous to the ordinary feldspars 
in direction. In the C atomic volume, as determined, it is iden- 
tical with the monoclinic feldspars. 'The atomic volumes of the 
feldspars will then stand as follows: - 
‘at . I) MONOCLINIC. 
e A ‘ x 
fete B. 0. 
Orthoclase, eae ‘ ; 1888 2313 604 
Ryacolite, Bie a Bie Weare 867 216°7 578 
~ Loxoclase, ; : ; ‘ 1063 2126 56" 
Baulite, . ‘ : - : 21781 21781 5585 
we Pitta go ee 224-98 573 
; Il. TRICLINIC. 
Thites 2 a om 1280: 213-4 55°67 
Labradorite, . ; ‘ ‘ 795° 198°9 53°03 
Oligoclase, hase) : 10383 20766 54-647 
Andesine, . ; é 2912-4 208 55" 
Anorthite, . : i . ‘ 1959 195-9 52-94 
Vosgite, .  . . 22665 197 5284 
Topaz and Andalusite approximately ?somorphous.—T he an- 
gle of the vertical prism of Andalusite is 91° 20’, and in Topaz 
a8 Written out in full, 
6[3A12 0342803] + [SAl2 F3-+2Si F3]. 7 
As this, excluding the fluorine, is the formula of Andalusite, the iso- 
morphism here pointed out may be a case of ordinary isomorphism. 
Manganocaicite.—This species is a trimetric carbonate of man- 
ng 
ganese, illustrating the remark on page 239. 
a 
? 
