1876.] The Flora of Guadalupe Island. 221 
It remains to observe that the phenomena of exact parallelism, 
or palingenesis, are quite as necessarily accounted for on the prin- 
ciple of acceleration or retardation as are those of inexact par- 
allelism, or coenogenesis. Were all parts of the organism accel- 
erated or retarded at a like rate, the relation of exact parallelism 
would never be disturbed, while the inexactitude of the par- 
allelism will depend on the number of variations in the rate of 
growth of different organs of the individual, with additions in- 
troduced from time to time. Hence it may be laid down that 
synchronous acceleration or retardation produces exact parallel- — 
ism, and heterochronous acceleration or retardation produces in- 
exact parallelism. 
In conclusion, it may be added that acceleration of the segmen- 
tation of the protoplasma or animal portion of the primordial 
egg, or retardation of segmentation of the deutoplasma or vege- 
' tative half of the egg, or both, or the same relation between the 
growth of the circumference and centre of the egg, has given rise 
ato the four types which the segmentation now presents. This 
analysis of the laws of evolution was tabulated as follows : — 
"E a T 
PEF ried 
38 2 3 S28 6 
pi ge TTTS 
E ae TS E 
Cr Se The 3S 
SETE guan 
Pree EFFE 
Ro 8.) Aal 
iti * * 
acceleration, Exact repetition. ri 
which proceeds by pein repetition. 5 : 
eterotopy. K ja 
` _.. Tetardation, § Exact atrophy. S 
Which proceeds by } Modified atrophy. * 
_— 
THE FLORA OF GUADALUPE ISLAND, LOWER CALI- 
FORNIA. ? 
BY SERENO WATSON. 
THe island of Guadalupe is in latitude twenty-nine degrees 
north, about one hundred miles from the coast of Lower 
California, and two hundred and thirty west of south from the 
town of San Diego, which is near the southern line of California. 
It is twenty-six miles in length in a north and south direction, 
with an average breadth of ten miles, and is traversed by a 
Mountain ridge, the central peak (Mount Augusta) having an 
tet from the Proceedings of the American Academy of Arts and Sciences, 
xi, 7 
