176 THE FLORAL WORLD AND GARDEN GUIDE. 
until the middle of March, when, with the aid of a little more water 
and the increased temperature of the season, they will begin to break 
naturally. If they are cut down in the autumn while ina green 
succulent state, you are liable to lose the old plant altogether, and, 
if not the whole of it, perhaps two or three of the side-shoots, which 
renders the specimen not a specimen, and, in fact, unfit for any 
purpose at all for a long time afterwards. In cutting down, do not 
cut too low, as they are at all times liable to die back an inch or two, 
and if cut higher than actually required, it is easier to rub away the 
top bud than it is to supply one where there is no growth to do it. 
The undermentioned comprise the best of those at present in 
cultivation, for pot culture:—A. I’. Barron, Coleshill, Corsair, De 
Lesseps, Diana, Harry King, Jealousy, King of the Forest, Lord 
Macaulay, Richard Cceur-de-Lion, Rienzi, Purple Gem, Purple 
Prince, Apple Blossoms, Lady Emily, Master Christine, Madame 
Rendatler, Mrs. F. Burnaby, Richard Wallace, Rose Bradwardine, 
Alice Spencer, Beau Villageois, Miss Gladstone, Madame Jean 
Sisley, Pioneer, President Thiers, Queen of Beauties, White Princess, 
White Clipper. 
The four best to grow for producing a succession of flowers — 
throughout the winter are—Veswvius, scarlet; Master Christine, 
pink; Jealousy, orange-scarlet ; and White Clipper, pure white. 
THE HYDRA. 
A GARDEN STUDY FOR THE MICROSCOPE. 
BY W. B. PRITCHARD. 
Continued from p. 305 (1875). 
Sy=2 ET us now, with the help of Dr. Deakin, examine more 
| carefully into the structure of these little animals, 
i which are endowed with such wonderful powers, in 
order that we may better understand its economy and 
- habits; and a few remarks and illustrations from 
the investigations of Corda will be perused with interest. This 
author has examined most carefully the Hydia fusca, and he con- 
siders the arms (tentacules) to be long, pellucid, extremely delicate 
tubes, of a membranous structure, and that they contain a semi- 
fluid albuminous substance, which in certain definite parts swells 
into wart-like knots, of a denser substance, and that these are 
arranged ina spiral manner, into which are attached numerous organs 
of touch, and also instruments by which it holds its prey. Within 
the tube, and running beneath these knots, are four longitudinal 
bands of muscular fibre, of a yellowish colour. With these fibres it 
is thought that the animal has the power of extending the arms. 
These muscular fibres are united to each other by transverse muscles 
of the same colour, and Corda considers that by these the animal is 
enabled to contract its arms, and fold them up like a fan. 
In tbe wart-like knobs of the arms are, according to Corda, the 
