450 
NATURE 
[JuLY 4, 1912 
is already considerable, and includes a “Flora 
Montana Formose” by the author of the work 
now under review, as well as a more comprehen- 
sive publication mainly compiled by Dr. Hayata 
at Kew. 
Although bearing a primary Latin title, the 
present work is written entirely in English in a 
clear and idiomatic style. As we learn from the 
“Introduction,” the Icones will contain 600 plates, 
illustrating nearly all the plants to be found in 
Formosa, and accompanied by descriptions. These 
will be issued yearly for fifteen years in separate 
numbers, each containing forty plates. Dr. 
Hayata’s estimate of the total number of vascular 
plants now known to inhabit the island is 2660 
species belonging to 836 genera and 156 families. 
There is a considerable endemic element in species, 
but the number of peculiar genera is relatively 
small. 
The “Icones” are excellently drawn and en- 
graved on copper, with ample floral analyses, and 
comprise the families Ranunculace to Umbellifere. 
In concluding this brief notice we strongly protest 
against the barbarous manner in which letterpress 
and plates are nailed together, with stout nails, a 
quarter of an inch within the margin. It was 
necessary, though difficult, to extract these already 
rusty nails before we could consult the book. 
W. Bortinc Hems ey. 
” 
LETTERS TO THE EDITOR. 
[The Editor does not hold himself responsible for 
opinions expressed by his correspondents. Neither 
can he undertake to return, or to correspond with 
the writers of, rejected manuscripts intended for 
this-or any other part of Naturr. No notice is 
taken of anonymous communications.] 
Hybrid Sea-urchins. 
It may interest readers of Narure to learn that this 
season we have been successful in crossing the two 
species of British sea-urchin, Echinus nuharis and 
E. acutus, at the Imperial College, and that we have 
reared the hybrid larve through their entire develop- 
mental cycle in our tanks, and have now hybrid sea- 
urchins creeping about. 
Further, in a culture of the larve of E. nuharis, 
which was instituted as a control, a puzzling barrel- 
shaped organism turned up. Microscopic examination 
revealed the fact that this organism had been derived 
from a larva in which a water-vascular system, with 
all its outgrowths, had been developed on the right 
side, as well as on the left, and which had completed 
its metamorphosis. The right water-vascular system, 
though provided with the typical number of fifteen 
tentacles, was smaller than the left, and was not 
parallel with it so far as the plane of the water- 
vascular ring was concerned. 
Last autumn I published an account of a fully 
developed larva of Ff. esculentus, which had two. water- 
vascular systems, but that larva had not meta- 
morphosed. The specimen which turned up this year 
has been suitably preserved, and an account of its 
anatomy will be published later. 
E.. W. MacBripe. 
Royal College of Science, South Kensington, 
London, S.W., June 21. 
NO. (2227, VOL, 89] 
July Meteor-showers. 
Tue following meteor-showers become due during 
the month of July : — 
Epoch July 5, 15h. 30m. 
fifth order of magnitude. Principal maximum, July 
4, 1th. 35m.; secondary maxima, July 2; ish., and 
July 3, 12h. 4om. 
Epoch July 5, 20h. 30m., 
third order of magnitude. 
(G.M.T.), approximately 
approximately twenty- 
Principal maximum, July 
4, 14h. 4om.; secondary maximum, July 4, 5h. 50m. 
Epoch July 8, 2h. 3om., twenty-first order of magni- 
tude. Principal maximum, July 6, 8h. 10m.; 
secondary maximum, July 4, 21h. 50m. 
Epoch July 8, sh., twenty-seventh order of magni- 
tude. Principal maximum, July 6, 18h. 30m.; 
secondary maxima, July 7, 17h. 15m. and 22h. 5om. 
Epoch July 10, 20h., eighth order of magnitude. 
Principal maximum, July 9, 13h. 52m.; secondary 
maximum, July 9, 11h. 25m. 
Epoch July 9, 3h., approximately twenty-fifth order 
of magnitude. Principal maximum, aa 10, 
toh. 1om.; secondary maxima, July 10, ith. 5m. and 
23h. 5m. 
Epoch July 11, toh. 30m., approximately seventh 
order of magnitude. Principal maxima, July 11, 
toh. 30m., and July 13, 7h.; secondary maximum, 
July 12, 15h. 
Epoch July 13, 15h., twelfth order of magnitude. 
Principal maxima, July 11, 19h. 30m., and July 13, 
14h. 50m.; secondary maximum, July 12, 8h. 1om. 
Epoch July 11, 5h., twenty-eighth order of magni- 
tude. Principal maximum, July 11, 21h. 5om.; 
secondary maximum, July 11, toh. 25m. 
Epoch July 14, 13h., eleventh order of magnitude. 
Principal maxima, July 14, 20h. 5m., and July 16, 
13h. 45m.; secondary maximum, July 15, th. 
Epoch July 15, 18h. 30m., eighth order of magni- 
tude. Principal maximum, July 16, th. tom.; 
secondary maximum, July 17, 11h. 25m. 
Epoch July 16, 2h. 30m., eleventh order of magni- 
tude. Principal maxima, July 16, 3h. tom., and 
July 17, 22h. 30m.; secondary maximum, July 16, 
12h. 35m. 
Epoch July 19, 1toh., ninth order of magnitude. 
Principal maximum, July 20, 22h. 15m.; secondary 
maxima, July 19, 15h. 45m., and July 21, 8h. 15m. 
Epoch July 21, 12h., approximately twenty-first 
order of magnitude. Principal maximum, July 22, 
1th. 1om.; secondary maxima, July 22, 13h. 30m., and 
July 23, oh. 55m. 
Epoch July 29, 3h., approximately second order of 
magnitude. Principal maximum, July 28, 2h. 50m. ; 
secondary maximum, July 27, 16h. 30m. 
Epoch July 27, 2th., twenty-second order of magni- 
tude. Principal maxima, July 28, 8h. 1om., and 
July 30, 3h. 35m.; secondary maximum, July 29, 
2oh.,. 50m. 
An important maximum of the month is the first 
principal maximum, which takes place shortly before 
midnight on July 4. Another maximum calling for 
special notice becomes due on July 11, 19h. 30m. 
There is considerable meteoric activity on July 16, 
highly concentrated maxima occurring on July 16, 
th. 30m. and 13h. 45m. Three maxima, belonging 
to the weaker epochs, deserve also special mention ; 
two of these occur on July 6 at 8h. tom. and 
18h. 30m. respectively, and the third, which is really 
stronger than either, on July 22, 11h. tom. 
Dublin, June 24. Joun R. Henry. 
pepethne 
