542 
NA DORE. 
[AZarch 24, 1870 
and foraminifera, than it did in the mollusca, of which a con- 
siderable proportion were common to both areas. The abun- 
dance and variety of animal life on a bottom of which the tem- 
perature is at least 2° (Fahr.) below the freezing-point of fresh 
water, is a fact which has all the interest of surprise ; and it is 
scarcely less remarkable that the forms of mollusks, echinoderms, 
and sponges, which seem to be the characteristic inhabitants of 
this cold area, should attain a very considerable size. The pre- 
cise limitation of the Globigerina-mud and of the vitreous sponges 
to the warm area, was a very striking manifestation of the influ- 
ence of temperature, and has very important geological bearings. 
Thirdly, they have largely added to the number of cases in 
which types that had been regarded as characteristic of earlier 
geological periods, and to have long since become extinct, prove 
to be still existing in the depths of the ocean ; and greatly in- 
crease the probability that an extension of the like method of 
research to more distant localities would produce even more 
remarkable revelations of this character. 
The doctrine propounded by Professor Wyville Thompson, in 
the report of the Zzghtning expedition, as to the absolute con- 
tinuity of the cretaceous formation with the deposit of globige- 
rina-mud at present in progress on the North Atlantic sea-bed, 
has received such striking confirmation from the discovery of 
the persistence of numerous cretaceous types, not merely in our 
own explorations, but also in those carried on by the United 
States Coast Survey in the Gulf of Mexico, that it may be fairly 
affirmed that the ozs proband: rests upon those who assert that 
the formation of true chalk has ever been interrupted since the 
cretaceous period. That period is usually considered to have 
terminated with the elevation of the cretaceous deposits of the 
European area into dry land. But according to the accepted 
doctrines of geology, it is highly probable that, coincidently with 
the elevation of the European area, there was a gradual subsi- 
dence of what is now the Atlantic sea-bed ; so that the Glodige- 
vine of the former area, with many accompanying types of 
animal life, would progressively spread themselves over the 
latter, as its conditions became favourable to their existence. 
And there seems no reason why they should not have maintained 
themselves in its deepest parts, through the comparatively small 
changes of level which took place in this portion of the earth’s 
crust during the Tertiary epoch. 
Fourthly, the /orcup~zze explorations have enormously ex- 
tended our knowledge of the British marine fauna ; alike by the 
discovery of new types, and by the addition of types previously 
known only as inhabitants of other localities.—The mollusca 
alone have as yet been fully examined ; and Mr. J. Gwyn Jef- 
freys, whose authority upon this part of the subject is not second 
to that of any other naturalist, reports as follows :—The total 
number of species of marine mollusca enumerated in his recently 
completed ‘* British Conchology” (excluding the Nudibranchs) 
is 451; and to these the Porcupine expedition has added no 
fewer than 117, or more than one-fourth. Of these as many as 
fifty-six are undescribed, whilst seven were supposed to be ex- 
tinct as Tertiary fossils. Sixteen genera, including five which 
are undescribed, are new to the British seas. ‘*‘ All that I can 
do,” he says, ‘* by continual dredgings in comparatively shallow 
water during the last sixteen years was to add about eighty spe- 
cies to the number described by Forbes and Hanley. I regard 
the present (although a large) addition as merely an earnest of 
future discoveries. In fact the treasury of the deep is inexhaus- 
tible.” The complete examination of the crustacea, which are 
in the hands of the Rey. A. M. Norman, and of the annelids, 
which have been undertaken by M. Claparéde and Dr. Macin- 
tosh, will probably yield results scarcely less striking. It is, 
however, in the echinoderms and sponges, which are being ex- 
amined by Professor Wyville Thomson; in the stony corals, 
which have been referred to Dr. P. M. Duncan; and in the 
foraminifera, which constitute the speaker’s own speciality, that 
the most interesting novelties present themselves. 
W. B. CARPENTER 
SCIENTIFIC SERIALS 
THE February number of the American Naturalist (Vol. iii. 
No. 12) contains only three original articles, and of these the first 
and most important is really a reprint of Professor Wyman’s 
observations on the development of the thornback, with a few 
introductory remarks on the natural history of the skates, by 
Mr. F. W. Putnam. The other two are the continuation of Mr. 
J. A. Allen’s notes on the rarer birds of Massachusetts, and a 
paper on common fresh-water shells, by Mr. E. S. Morse. 
Professor Williamson’s article on Bathybius is reprinted from 
the Popular Science Review. 
A SHORT paper appears in the last number of Troschel’s 
Archiv fur Naturgeschichte from the pen of Dr. A. A. Krohn, 
on the earliest development of the Botryllus stock, which, as 
most of our readers are probably aware, constitutes one of the 
Tunicate Molluscs analogous to the misshapen bodies found so 
commonly on our sea coasts, and known as ‘‘ dead men’s 
fingers.” Hitherto certain processes found at the anterior end 
of the larva have been regarded as the germs or buds of new 
individuals which subsequently become completely differentiated, 
but M. Krohn shows that these are clavate processes, constituting 
the first rudiments of the blood-vessels which make their appear- 
ance soon after the metamorphosis of the larva. After a short 
time the vessels begin to branch, each branch terminating in a 
dilated ccecal enlargement resembling the calyx of the common 
Lyrica tetralix in form, and at this time a round projection appears 
on the right side of the body, near the heart, into which a stream 
of blood from the mother sets, and having circulated around it 
returns to its starting point. It now, curiously enough, begins, 
together with the mother animal, to shrink, and finally disappears, 
and in its place a daughter Botryllus is developed. The daughter 
Botryllus forms two buds, a right and a left, while itself passes 
through the same stages as the original mother, becoming also 
fluid and disappearing. The two buds of this third generation, 
when fully developed, have their cloacal apertures opposed, and 
each gives off two buds which are arranged with the parents in 
a circular manner, and these four buds may again give off others, 
and so regularly arranged systems of the animals are produced, 
the vascular system undergoing corresponding development and 
extension. The blood contains colourless corpuscles, and under 
certain circumstances a number of dark pigment granules present 
in the bodies of the successive generations, on undergoing atrophy 
appear to gain entrance into the circulating fluid. 
THE Revue des Cours Scientifiques for the 19th inst. contains a 
report fof a lecture by M. Claude Bernard on the history of 
medical science and its actual condition ; of one by M. Harny, 
on human remains in the tertiary deposits in America, and on 
the theories of multiple centres of creation ; and of one by Dr. 
Bertillon on the mortality of different departments of France. 
In the just published Proceedings of the Royal Society of 
Ldinburgh for the session 1868-69, Professor Allman gives a 
description of Rhabdopleura, a new genius of Polyzoa. The 
ccenzcium or common stem consists of a branched tube partly 
adherent and partly free, the free portion forming tubes of egress 
through which the polypides move in the acts of exsertion and 
retraction. In the walls of the adherent portion a rigid chitinous 
rod is developed along their attached side, from distance to 
distance, each by a flexible cord or funiculus. The polypides are 
hippocrepian, and each carries a shield-like process on the 
hzemal side of its lophophore, external to the tentacular series. 
In development the polypide at an early stage is included between 
two fleshy plates on the right and left sides respectively, and 
which are partially united. For some time the two plates keep 
pace with the general development of the bud, but ultimately 
they cease to increase in size, and then remain as the shield- 
like processes carried by the lophophore of the polyzoon. Professor 
Allman regards these plates as representing the right and left 
lobes of the mouth in a Lamellibranchiate Mollusk, from 
which it follows that the relations of the Polyzoa are more 
intimate with the Lamellibranchiata than with the Brachiopoda, 
with which of late years they have been associated, but whose 
mantle lobes lie dorsally and vertically, instead of lying right 
and left as in the Lamellibranchiata. The lophophore of the 
Polyzoa he considers to have its representative in the labia] 
palps of the Lamellibranchiata. The animal was obtained by 
the Rey. A. Norman and Mr. J. Gwyn Jeffreys in the course of 
deep-sea dredging in Shetland. 
THE Journal of the Chemical Society for February is mainly 
occupied by a long paper by Mr. F. A. Abel, entitled “ Contribu- 
tions to the history of explosive agents,” abstracted from the 
Philosophical Transactions for 1869. There are also shorter 
articles on nontronite, and on a new chromium oxychloride, by 
Dr. T. E. Thorpe, and observations on the solution of gases in 
water by Dr. Williamson. 
THE Monthly Microscopical Fournal for March contains the 
President’s Address, an obituary notice of the late J. J. Lister, 
F.R.S., and articles on the structure of the stems of the arbor- 
escent Lycopodiacee of the coal measures, by Mr, Carruthers, and 
on the mode of examining the microscopic structure of plants. 
