124 
NATORE 
[APRIL 2,. 1984 
in Cambrian times, and these he terms respectively the 
Shantung Province (including Manchuria and Shan-si), 
the Punjab Province (including Yun-nan), and the 
Siberian Province. 
Passing to the description of the new genera and 
species from China, we cannot help regretting that 
there is a general absence of individual comparison 
of the new forms with previously established or well- 
known species from other lands. It would have been 
especially valuable to have had their affinities discussed 
by Dr. Walcott, with his ripe experience and world- 
wide knowledge of Cambrian fossils. He indeed ex- 
presses the opinion that the excellent illustrations of 
the new species will enable other investigators to 
pursue such a study as occasion requires; but no 
plates or figures, however good, can remedy such a 
defect in the original descriptions, and this omission 
robs the memoir of much of its value. 
The Ordovician fossils described in the second sec- 
tion by Dr. Weller, have been obtained partly from 
Shantung and partly from Ssi-ch’uan. The former 
are very poor and few in number, and no specific 
determinations were found possible, but their strati- 
graphical horizon is believed to be Middle Ordovician. 
The fossils from eastern Ssi-ch’uan are quite different 
in character and in much better preservation. They 
were obtained from a thick limestone resting con- 
formably on the Cambrian, and consist chiefly of 
brachiopods and trilobites, some species of which were 
described in t901 by Martelli from Shen-si. Richt- 
hofen’s Ordovician fossils from northern Ssi-ch’uan, 
collected more than thirty years ago, are regarded 
as indicating the same geological horizon which Dr. 
Weller correlates with the Mohawkian (Middle Ordo- 
vician) of North America. The fossiliferous Ordo- 
vician beds of the central Himalayas, to which he 
makes no reference, have been regarded as of the 
same age. There is no similarity to the Ordovician 
faunas of eastern Yun-nan and Tonkin or of the 
Northern Shan States, but some species appear com- 
parable or closely allied to Spiti forms; and in south- 
western Yun-nan it is probable that the Ssi-ch’uan 
fauna is represented. A conclusion of special interest 
at which Dr, Weller arrives is that there is a mixture 
of North American and Baltic forms in China, as in 
the Himalayas, where, however, the American element 
seems to be stronger. 
The Carboniferous fauna described by Dr. Girty 
from Shantung, Shan-si, and Ssi-ch’uan is very scanty 
and of peculiar facies, but seems remotely allied to 
Russian and Indian faunas, and is considered to be 
of Upper Carboniferous (Pennsylvanian) age, with the 
exception of a few very doubtful fossils. The rich 
Middle and Upper Carboniferous faunas described by 
Kayser, Loczy, Mansuy, and Deprat from other parts 
of China appear to be unrepresented. 
BR. (CREED: 
MARINE BIOLOGY. 
aes. life-histories of the Pacific Coast salmon and 
the halibut caught off the west coast of North 
America form the subject of two papers just published 
by Dr. J. P. McMurrich in vol. vii. of the Transactions 
of the Royal Society of Canada. In this work the 
author puts the method of scale examination to a 
somewhat severe test. It is fairly certain that. this 
line of investigation must be regarded only as supple- 
mentary to detailed research by means of fishery 
experiments and statistical studies; such is the ex- 
perience of most workers in Europe. Yet Dr. 
McMurrich does not hesitate to describe the conclu- 
sions that may be deduced from the study of the 
scales of twenty-two, or ten, or even three fishes, as 
NO. 2318, VOL. 923] 
‘remarkably definite.’”’ The species of Oncorhynchus 
(the Pacific salmon) spawn only once in their life- 
times. The Pacific halibut becomes mature in its 
eighth year, and then enters upon a period of repro- 
ductive maturity. The ova ripen gradually, and 
‘spawning is not a matter of a few days or even 
weeks, but is prolongea over, it may be, several 
years.’’ This is too exceptional and improbable a 
result to deduce from a microscopic examination of 
the scales of three fishes, especially when the author 
admits that practically nothing is known as to the 
life-history of the halibut in North American waters. 
It is also incorrect to say that planktonic ova of this 
fish have not been found in European waters. Less, 
perhaps, is known about the halibut than most other 
Pleuronectids, but our ignorance is not such an utter 
blank as is suggested in the paper noticed. 
Part i. of the Journal of the Marine Biological 
Association, published in November, 1913, contains 
papers dealing with varied aspects of marine biology. 
Mr. J. H. Orton, in a most useful paper, describes 
the functioning of the ciliary mechanisms on the gills 
of Amphioxus, Ascidians, and Solenomya. English 
writers, apparently accepting as correct the earlier 
work of Fol, have described food collection as occur- 
ring in the endostyle of Ascidians, the solid particles 
being then conducted along the peripharyngeal 
grooves, and so into the dorsal groove. Mr. Orton 
points out that no food-matter at all is taken up by 
the endostyle. The latter secretes mucus, which is 
then driven dorsally over the pharynx to ‘the dorsal 
groove. Essentially the same mode of functioning 
of the ciliary tracts occurs both in Amphioxus and 
Ascidians. The pharynx in these animals, and the 
gills in Lamellibranch molluscs, are not respiratory 
mechanisms, but organs which function as water- 
pumps and food-collectors. In the same number of 
the journal there is an account of some very interest- 
ing experiments made by Mr. J. Gray with the object 
of investigating the chemical and physical changes 
which occur when the egg of the sea-urchin is natur- 
ally fertilised. The entrance of the sperm into the 
egg raises the electrical conductivity of the latter, the 
change attaining a maximum within ten minutes of 
the addition of the sperms to the ripe eggs. The egg- 
membrane in the unfertilised condition is remarkably 
impermeable to electrolytes, its surface being 
polarised. Probably the entrance of the sperm effects 
depolarisation and increases the permeability of the 
membrane to ions, but in some fifteen minutes 
polarisation again occurs, and the egg returns to its 
electrical state prior to fertilisation. Five other papers 
in the journal are written by zoologists of University 
College, Aberystwyth, and deal with sea-anemones, 
with the habits of the Galatheidea, and with the 
littoral fauna of Cardigan Bay. Dr. Th. Mortensen 
writes also on the development of some British 
Echinoderms. This number of ‘the journal is alto- 
gether a very interesting one. tbl b= 
CRYSTALLINE <STRUGLURES Ass, 
REVEALED BY X-RAYS.! 
HE analysis of crystal structure by means of 
X-rays depends on the fact that a pencil of 
X-rays of uniform quality is reflected by a crystal 
face when, and only when, it meets the face at exactly 
the proper angle. As we shall see presently, the 
effect depends on the regularity of the crystal structure 
according to which the atoms of the crystal are 
arranged in planes, which are parallel to the face and 
regularly spaced. There is a certain relation between 
1 From a lecture delivere| before the Manchester Literary and Philo- 
sophical Society on March 18, by Prof. W. H. Bragg, F.R.S. 
