122 
as the recent remarkable displays have been 
attributed to the volcanic dusts of Krakatoa. 
The peculiar phenomena in the skies, like 
those described, were not noticed at Tientsin 
in the spring. This may be accounted for by 
atmospheric conditions being changed, and 
the air at this season of the year being over- 
charged with too much fine material derived 
from the dust-storms which form, during March 
and April, so marked a feature of the climate of 
northern China. I think it quite probable, how- 
ever, that red skies, similar to those recently 
observed in various parts of the world, may at 
times be seen throughout the winter by foreign 
residents at Peking and Tientsin. 
A few more words about loess-dust. During 
the winter referred to I was much interested 
in the question of the loess that was annually 
being removed from the land and carried out 
to sea, and not only was impressed with the 
amount transported by streams, but was led to 
believe that a not inconsiderable quantity was 
borne eastward by the prevailing winds, and 
finally precipitated upon the ocean. Inquiries 
brought out the fact, that, in the China seas, 
ships many hundred miles from land frequently 
report showers of fine material falling upon 
the decks, which in many cases have been 
wrongly regarded as deposits of volcanic dust. 
In conversation with the captain of the steam- 
ship China, on the passage from Yokohama to 
Hong Kong in the autumn of 1879, he nar- 
rated his experience in a dust-storm, while 
passing over the same route in the preceding 
spring. ‘The storm occurred April 25, in lati- 
tude 29°, longitude 128°. It lasted twelve 
hours, with a heavy wind blowing steadily from 
the north-west. Every thing on board was 
coated with an excessively fine dust, which, as 
the captain expressed it, ‘‘ was so thick that 
it could be taken up with the fingers like so 
much snuff.’’ From the rigging, one of the 
sailors, under orders from the captain, collected 
with a knife-blade a large amount of the dust, 
samples of which he forwarded to London for 
examination. Now, I very well remember that 
in April the whole plain of northern China was 
enveloped in several severe dust-storms ; two 
of them, at least, having a duration of three 
days each, and filling the air at times with 
dust, so as to completely obscure the sun. 
There is no question in my mind but that the 
material which fell upon the steamship came 
from the loess of China; and I believe that a 
great deal of the so-called volcanic dusts 
which are often reported as observed at sea 
are, at least in Chinese waters, derived from 
loess-deposits. ARNOLD HAGUE. 
SCIENCE. 
THE EVOLUTION OF THE CEPHALO- 
PODA.—I. 
CEPHALOPODS, or cuttlefishes, have struc- 
tural peculiarities which make them the most 
favorable subjects now known for the special 
study of the problems and laws of the evolu- 
tion of forms in time. In two of the orders 
the animals were shell-covered ; and the shell 
in these is so built that it preserves, even in 
the fossils, the embryo, the young shell, and 
all its stages to the full grown. Then, passing 
on into old age, it shows in the senile period a 
series of retrograde transformations, often re- 
versing its adult condition and aspect. This 
record of the entire life is fuller than any one 
who has not minutely studied this type can 
imagine from his experience in other branches 
of the animal kingdom. It is not only in itself 
a complete cycle of changes, and these of no 
slight or doubtful character, but the external 
records of the shell-structure, apertures, and 
other parts, are supplemented by the hard por- 
tions of two internal structures, which are pre- 
served, and also change in accordance with the 
age of the shell. We have, therefore, in every 
well-preserved specimen, the unique advantage 
of being able to study the complete cycle of its 
individual life in three distinct sets of organic 
parts. Wecan therefore compare the changes 
which we observe in the individual with the 
modifications which the group has undergone 
in its progression or retrogression in geologic 
times with a certain completeness of the evi- 
dences, at present unattainable in any other 
class of animals. In the Belemnites, the third 
order, the shell and its parts are much less 
instructive; and finally, in the fourth, the 
Sepioidea, it is so much reduced, and so 
frequently absent, as to lose very largely in 
this respect. 
The class has two sub-classes, Tetrabranchi- 
ata and Dibranchiata. ‘These were established 
by Richard Owen as orders, —a purely techni- 
cal difference, which does not change in any 
way the value of the structural distinctions as 
given by this eminent naturalist. The Tetra- 
branchiata are shell-covered ; and they are rep- 
resented by the modern Nautilus, the only 
existing genus. The Dibranchiata are de- 
scendants of the former, but enclosed the shell, 
and resorbed it in many forms, so that they 
appear as naked animals. The cuttlefishes, 
squid, devil-fishes, etc., are existing types. In 
studying these types, the author has been led i 
to adopt a new method of characterizing the 
divisions, and besides the old structural dis- 
tinctions, which are still available, to apply the 
3 Ate Oust Sa 
(Vou. III., No. 52. ‘ 
