152 
NATURE 

[Sune 22, 1871 

fauna of Siberia, its uniformity and conformity to the European 
fauna, on the meaning to be given to the species, on their 
variability and on the multiplicity of false ones published, on the 
complexity of their respective gengraphical areas, on their ex- 
tinction and replacement by others, &c., are deserving of the 
careful study of all naturalists. L. v. Schrenck’s Mollusca of 
the Amur land or Mantchuria (reviewed in the ‘‘ Zoological 
Record,” iv. p. 504) is equally to be recommended for the manner 
in which the specific relations, the variability, affinities, and 
geographical distribution of Mantchurian Mollusca are treated. 
The publications of the first meeting of the Association of 
Russian Naturalists include a review of the Crustacea of the 
Black Sea by V. Czerniavski, an account of the Annulata Chee- 
topoda of the Bay of Sebastopol by N. Bobretzki, and a paper 
on the zoology of the Lake of Onega and its neighbourhood by 
K. Kesslar, including a review of the fishes, Crustacea, and 
Annulata of the Lake of Onega, and of the Mollusca collected in 
and about the Lakes Onega and Ladoga, and a list of the butter- 
flies of the Government of Olonetz. The historical and scientific 
memoirs published by tbe University of Kazan, of which several 
volumes have recently reached us, include a systematic enumera- 
tion and description of the birds of Orenburg (329 species), with 
detailed notes of their habits, &c., by the late Prof. E. A. Evers- 
mann, edited after his death by M. N. Bogdanoff, forming an 
Svo volume of 600 pages in the Russian language. 
There is not in Russia at the present moment sufficient encou- 
ragement on the part of the public to induce the publication of 
independent biological works beyond a few popular handbooks ; 
but the Imperial Academy of Petersburg has, on the other hand, 
been exceedingly liberal in the assistance it affords, and active 
in its issue of Transactions with excellent illustrations, as 
well as of its bulletin of proceedings. The volumes recently 
received include J. F. Brandt’s ‘‘ Symbol Sirenologicse” and 
researches on the genus /yrax (reviewed in ‘‘ Zoological 
Record,” v. p. 3, and vi. p. 5), A. Strauch’s Synopsis of 
Viperidze, with full details of their geographical distribution, E. 
Metschnikoff’s studies on the development of Echinoderms and 
Nemertines, and N. Miklucho-Maclay’s Memoir on Sponges of 
the N. Pacific and Arctic Oceans, with remarks on their extreme 
variability inducing the multiplication of false species. In botany, 
Bunge’s Monograph of the Old-World species of Astragalus is 
the result of many years labour and careful investigation. The 
eight sub-genera and 104 sections into which this extensive genus 
is divided appear to be very satisfactory ; but the species (971) 
are probably very much too numerous, and we miss that com- 
parison with American forms which, considering the very 
numerous cases of identity or close affinity, is essential for the 
due appreciation of the N. Asiatic species. Bunge has also 
published a monograph of the He/iotropia of the Mediterraneo- 
Oniental region in the Bulletin of the Society cf Naturalists of 
Moscow, which continues its annual volumes. The parts re- 
cently received continue several of the botanical enumerations 
already noticed, together with various smaller entomological 
papers. 
( Zo be Continued) 


GEOLOGY 
On the Supposed Legs of the Trilobite, Asaphus 
platycephalus* 
AT the request of Mr. E. Billings, of Montreal, I have re- 
cently examined the specimen of Asaphus platycephalus belonging 
to the Canadian Geological Museum, which has been supposed 
to show remains of legs. Mr. Billing, while he has suspected 
the organs to be legs so far as to publish on the subject, + has 
done so with reserve, saying, in his paper, “that the first and 
all-important point to be decided. is whether or not the forms 
exhibited on its under side were truly what they appeared to 
be, locomotive organs.”’ On account of his doubts, the speci- 
men was submitted by him during the past year to the Geological 
Society of London; and for the same reason, notwithstanding 
the corroboration there received, he offered to place the specimen 
in my hands for examination and report. 
Besides giving the specimen an examination myself, I have 
submitted it also to Mr. A. E. Verrill, Prof. of Zoology in 
* From the American Yournal of Science and Arts, Vol. 1, May, 187. 
_+ Q J. Geol. Soc., No 104, p. 479, 1870, with a piate giving a full-sized 
view of the under surface of the trilobite, a species that was over four inches 
in length. 


Yale College, who is well versed in the Invertebrates, and to 
Mr. 5. I. Smith, assistant in the same department, and excellent 
in crustaceology and entomology. We have separately and to- 
gether considered the character of the specimen, and while we 
have reached the same conclusion, we are to be regarded as in- 
dependent judges. Our opinion has been submitted to Mr, 
Billings, and by his request it is here published. 
The conclusion to which we have come is that the organs are 
not legs, but the semi-calcified arches in the membrane of the 
ventral surface to which the foliaceous appendages or legs were 
attached. Just such arches exist in the ventral surface of the 
abdomen of the Macrura, and to them the abdominal appendages 
are articulated. 
This conclusion is sustained by the observation that in one 
part of the venter three consecutive parallel arches are distinctly 
connected by the intervening outer membrane of the venter, 
showing that the arches were plainly 77 ¢he membrane, as only 
a calcified portion of it, and were not members moving free 
above it. This being the fact, it seems to set at rest the question 
as to the legs. We would add, however, that there is good 
reason for believing the supposed legs to have been such arches 
in their continuing of nearly uniform width almost or quite to the 
lateral margin of the animal; and in the additional fact, that 
although curving forward in their course toward the margin, the 
successive arches are about equidistant or parallel, a regularity 
of position not to be looked for in free-moving legs. The 
curve in these arches, although it implies a forward ventral ex- 
tension on either side of the leg-bearing segments of the body, 
does not appear to afford any good reason for doubting the 
above conclusion. It is probable that the two prommences on 
each arch nearest the median line of the body, which are rather 
marked, were points of muscular attachment for the foliaceous 
appendage it supported. 
With the exception of these arches, the under surface of the 
venter must have been delicately membranous, like that of the 
abdomen of a lobster or other macruran. Unless the under 
surface were in the main fleshy, trilobites could not have rolled 
into a ball. 
James D. DANA 

SCIENTIFIC SERIALS 
Annales de Chemie et de Physigue. The whole of the last part of 
the ‘‘ Annales” is occupied by M. Berthelot’s A/éthode universelle 
pour réduire et saturer @hydragéne les composes organiques, which 
is a vésumé of the elaborate and exhaustive researches on the 
action of hydriodic acid on organic substances in which he has 
been engaged for the last three or four years. Most of the 
results have been already published from time to time in the 
Bulletin de la Société Chimigue de Paris, and this classical re- 
search is now completed by the publication of the details of the 
methods of analysis and the thermochemical considerations in- 
volved. The author has found that any organic compound can be 
transformed into a saturated hydro-carbon, having, in general, the 
same number of atoms of carbon as the original substance, by 
heating it for a sufficient length of time to a temperature of 
275 C., with a large excess of an aqueous solution of hydriodic 
acid of the specific gravity of 2:0. The proportion of the acid 
is varied according to the nature of the substance submitted to 
its action, twenty or thirty parts being sufficient to reduce an 
alcohol of the fatty series, whilst a member of the aromatic 
series and such substances as bitumen, wood charcoal, 
and coal, require, at least, one hundred times their weight ; 
the large excess of acid serving the purpose of dissolving 
the iodine set free during the reaction, thus preventing its 
destructive action on the organic compound, and also in allow- 
ing the quantity of hydriodic acid necessary for the reduction 
ot the substance, to be withdrawn from the solution without re- 
ducing its strength so ‘ar that the reaction ceases. One of the 
most remarkable results exhibitedin the application of this method 
is that of the direct transformation of benzene into the saturated 
hydrocarbon, hexylene hydride, C; Hg + 8 HI = C, H,,+ SI, 
affording, as it does, an instance of a direct passage from the 
aromatic to the fatty series. When other members of the 
phenyl series are treated with hydriodic acid, the ultimate pro- 
duct is the same; but there is an intermediate step in the 
reaction, resulting in the formation of benzene, which, by the 
continued action of the acid, is transformed into the corresponding 
saturated hydrocarbon, The fifth and last part of the paper is 
