324 
NATURE 
[JANUARY 31, 1907 
ject of the two chief original articles in the Journal of 
the South African Ornithologists’ Union for December 
last. ; 
In the fourth volume (pp. 173-192) of Marine Investi- 
gations, South Africa, Dr. W. G. Ridewood describes a 
new species of the hemichordate genus Cephalodiscus, 
obtained from a considerable depth in the Cape seas. 
The new form brings up the number of known species to 
seven. 
Tue report of the Felsted School Scientific Society for 
1906 is illustrated with reproductions of photographs taken 
by the members of that body. The most interesting of 
these represents a nest, with eggs, of a moorhen, built 
on some sticks in the river Pett, about 3 feet from the 
bank, with the base of the structure touching the water. 
The society appears to be in a thriving condition. 
Tue Hon. Walter Rothschild has just presented to the 
British Museum (Natural History) a fine mounted speci- 
men of a male Alaskan elk, or moose (Alces machlis 
gigas), which has been temporarily placed in the central 
hall behind the African elephant. The Alaskan elk, we 
may remind our readers, is the largest representative of 
its species, although some of the estimates of its height 
are almost certainly exaggerated. 
WE. have received the report of the museum committee 
for the County Borough of Warrington for the past year. 
It appears that Warrington was the first town in the 
United Kingdom to establish (in 1848) a rate-supported 
public library, and a tablet with an inscription to that 
effect has recently been placed in the building. The 
excavation of the site of the Roman station at Wilderspool 
has, for the present, been brought to a conclusion, and 
the spoils are in process of being arranged for exhibition. 
THE fourth part of vol. iii. of the Transactions of the 
Hull Scientific and Field Naturalists’ Club contains a 
coloured plate of the four known British-laid eggs of 
Pallas’s sand-grouse. These constitute two complete 
clutches, both taken on the high wolds near Beverley in 
1885, one on June 15 and the other on July 5. The only 
other known instance of this species breeding in the British 
Isles rests on the evidence of a young bird found in 
Morayshire. The eggs are the property of Mr. T. Audas. 
Unper the title of ‘‘ Nature Names in America,’’? Mr. 
Spencer Trotter, in the January number of the Popular 
Science Monthly, gives some interesting information with 
regard to the origin of the vernacular designations of 
many of the animals and plants of the United States. 
Raccoon, opossum, skunk, chipmunk, and moose are, it 
appears, taken direct from the Algonquin language. Miss 
L. P. Bush contributes a translation of a valuable article 
by Mr. Anton Handlirsch, of the Vienna Museum, on 
fossil insects and the development of the class Insecta. 
Many naturalists will remember that after the fresh- 
water jelly-fish Limnocodium was discovered in 1880 and 
its little polyp stage also described, a very similar polyp, 
the Microhydra ryderi, was found in a back-water of the 
Delaware River, near Philadelphia, in the United States. 
In 1897 the veteran naturalist Mr. Edward Potts, of 
Philadelphia, described in the American Naturalist, with- 
out illustrative figures, the production of a medusa or jelly- 
fish by this little Microhydra. The observation escaped 
the notice of most zoologists, and it is therefore a matter 
of congratulation that Prof. Ray Lankester has obtained 
from Mr. Potts a full description of the budding of Micro- 
NO. 1944. VOL. 75] 
| 
hydra and of the medusa produced by it, accompanied by 
numerous excellent drawings. ‘These are published in. the 
December (1906) number of the Quarterly Journal of; Micro- 
scopical Science. Figures are given for comparison of the 
medusa and polyp: (Limnocodium) from Regent’s Park 
(1880), and of the medusa of Lake Tanganyika (Limnoc- 
nida) described in 1893. Mr. Potts sent a preserved speci- 
men of the North American fresh-water medusa to Prof. 
Lankester, who submitted it for examination to Mr. E.'T. 
Browne, well known as a specialist on the medusz, and 
a report and figures by him are published together with 
Mr. Potts’s memoir. The medusa of Microhydra differs 
greatly from that of Limnocodium, although the polyp form 
has many curious points of resemblance in the two genera. 
Only very young liberated medusz of Microhydra have, as 
yet, been observed. There is obviously an opportunity for 
further study of a very interesting kind in regard to: this 
last discovery made by Mr. Edward Potts, so well known 
ta zoologists by his researches on fresh-water sponges. 
Tue methods of preparing an accurate survey of the 
plants growing in a plot of pasture or meadow-land is the 
subject of a small brochure by the Rev. E. A. Woodruffe- 
Peacock, published. as No. 9 of the Rural Science Series. 
The system -here explained in detail is recommended to the 
consideration of students taking up flora analysis from a 
biometric standpoint. 
SELECTING as his subject the financial success of forest 
management, Dr. W. Schlich, F.R.S., delivered a lecture 
before the students of the Royal Agricultural College, 
Cirencester, that is published in the December (1906): 
number of the Agricultural Students’ Gazette. “While the 
lecture contains no new facts, it provides an excellent 
summary of guiding principles, and as a practical illus- 
tration Dr. Schlich quotes from the working plan drawn 
up by him for the Alice Holt crown forests in Hampshire. 
A QUESTION that must frequently occur to fruit-growers 
is concerned with the causes that control the time of 
flowering of trees. An attempt to calculate in a general 
way the number of heat units received in different years 
is discussed by Mr. E. P. Sandsten in Bulletin No. 137 
issued from the agricultural experiment station of the 
University of Wisconsin. As would be expected, conditions 
during the previous summer and autumn are no less 
potent than temperatures in the spring, while less important 
factors are connected with the condition of the soil and 
the characteristics or state of health of each individual 
plant.. The author mentions that the number of units 
required to bring a tree to flower varies from year to year, 
but does not state whether the proportion of heat units 
required by different varieties remains constant, although it 
would appear that data suitable for deciding this point 
were collected. 
Tue Engineering Standards Committee has issued tables 
of British standard Whitworth screw threads, of British 
standard fine screw threads, and of British standard pipe 
threads. The tables can be obtained, post free, for a 
penny, from the offices of the committee, 28 Victoria 
Street, Westminster. 
In the discussion on Mr. H. Campbell’s paper on suction 
engines and gas plants, read before the Institution of 
Engineers and Shipbuilders in Scotland (Transactions, vol. 
1., part iii.), Mr. F. J. Rowan gave a bibliography of the 
subject, bearing witness to the enormous amount of in- 
vestigation and research that has been carried out during 
the past two or three years. 
