132 
NATURE 
| Zune 10, 1886 
Occultations of Stars by the Moon (visible at Greenwich) 
Corresponding 
angles from ver- 
June Star Mag. Disap. Reap. exiomeneior 
inverted image 
h. m. h. m. a Ay 
18 ... B.A.C. 6536 64 25 Olea ee 85 334 
TO)... B.A.C.. 7145 6%)... 20 AO) ...822)05 113 186 
Variable Stars 
Star R.A. Decl. 
h m Oe h. m. 
U Cephei © 52:2)... 81 16)N.<... June 145) 1550772 
ap CR 4 SS 
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S'Gancri «2. 8! 3774 «2 10) DPN ee een eemeaaa72 
W) Virginis <.. 9.0. 13) 202)... 2747S aesowns | eR eo)? 
5 Libre Se eeone fey: eerie Wished. AA) lish, @ RA a 
9» 19, 23 58 m 
Ui Corons! 6s. 2:6, D5N13°6)-.. 32) 4) Nev. ae eget On2 
U Ophiuchis.. - ... 171078) 2s. Wri 20 No cya Oe a 772 
” 16, 21 55 m 
XM (Sapittaritl.) (20 17 AO) ...'27) 47 Se Wiis LO NERemZOne 
W Sagittarii a WV Reteeeemsomshowa, op ich © Gig 
U)Sagittarit;  .  1892552).55119 T2iSt t..iensy eLO meme ater 
Bileyrees es eee eee TOL 4529) nc. SSL4UINe, ace) is, LOMO. 
SiMulpeculee =. (OVA S57) .0- 27 ONN: cecueesmmge M 
my Aquila’ 5. 22. 10) 46°7... O743.Ni- yO nmezECOR. 
R Lacerte ... 22:38 2.4 47 Noe Os M 
M signifies maximum ; 7 minimum. 
BIOLOGICAL NOTES 
DEVELOPMENT OF OPHIOPHOLIS AND ECHINARACHNIUS.— 
In the last series of studies from the Newport Marine Zoological 
Laboratory we find a memoir by Mr. Walter Fewkes, on the 
development of an Ophiuroid (Op/zopholis aculeata, Gray) and 
of an Elypeastroid (Zchinarachnius parma, Gray). But few 
observations have been published on the metamorphosis of 
Ophiopholis, and these often misleading. The eggs would appear 
to be extruded separately into the water, and the young pass 
through a metamorphosis in which a pluteus-larva is formed ; 
the development of this pluteus is different from that of any 
described Ophiuran, though allied to that in Ophiothrix. The 
ova were voluntarily shed by the female on August 17; they 
were fertilised outside the body, and appeared to be very hardy. 
The yolk has a central and a peripheral region, which are dis- 
tinguishable in the eight-cell and previous stages of segmentation. 
The cleayage is like that of other Echinoderms. A gastrula is 
formed by the invagination of the blastoderm, and consequently 
the stomach of the pluteus is an infolded wall of the blastoderm, 
and not formed by delamination from the cells in the cavity. 
The mesoderm-cells originate in two lateral clusters. The 
oldest pluteus observed was a little more than three days old ; 
they, however, appeared to be easily raised, and it is to be 
hoped that they will be yet traced to an adult form. In 
Echinarachnius the sexes are distinct, and in some cases there were 
colour-distinctions. In the experiments on the ovum of Z. parma, 
artificial fertilisation was resorted to from the middle of July to 
the end of August; it was easily effected. In its mode of seg- 
mentation it resembles that of other Echinoderms. It has no 
polar globules, but possibly these may be formed while the egg 
is in the ovary. Asin some other Echinoderms, a gastrula is 
formed by invagination, The pluteus figured by A. Agassiz in 
the revision of the Echini as probably that of Echinarachnius 
proves to belong to this species at about a week old. The de- 
velopment of the young Echinarachnius on the water-tube of the 
pluteus resembles that of other sea-urchins, The rosette-form 
of the water-tubes described in other Echinoderms also occurs. 
The first-formed calcareous deposits of the test are trifid in form, 
and vary in number in different specimens. The extremity of 
each trifid division bifurcates later in its growth, and the cal- 
careous body thus formed appears to be inclosed in a transparent 
wall, which has a spherical outline. Spines are very early 
formed, and are proportionately very large as compared with 
those of the adult. The various stages are illustrated in nume- 
rous figures on eight, in several cases folding, plates.—Au/?. 
Les. Comp. Anat. Harvard College, vol. xii, No. 4, March 
1886, 
THE LEECHES OF JAPAN.—In the April number of the 
Quarterly ~ournal of Microscopical Science, Dr. C. O. Whitman 
publishes the first hundred pages of a memoir on the leeches of 
Japan. The material for the study was collected while the 
author was connected with the University of Tokio (1879-81). 
The coloured drawings accompanying the memoir were executed 
by Mr. Nomura, a young Japanese artist, and they well deserve 
the remarks of ‘he author: ‘‘Mr. Nomura’s attention to the 
minutest detaius, his infinite patience, trained eye, and his 
remarkably skilful brush, have given results that are marvels for 
neatness and accuracy.” The first part of this study treats of 
the land leech (Hemadipsa japonica), the medicinal leech 
(Hirudo medicinalis), and of three species of toothless leeches, 
which form a new genus, Leptostoma. It also contains a com- 
parison of a few species from Europe, Asia, and America, and 
a considerable portion is devoted to a comparative study of the’ 
different genera, in the endeavour to find a satisfactory basis of 
classification. This has in a great measure been found in a law 
of abbreviation of the somites, which, in addition, gives a key 
to the phylogeny of the genera. The land leech is shown to 
be a highly instructive and specialised form. The genus Hirudo 
has been re diagnosed (p. 364), and while internal structure has 
been dealt with to only a very limited extent, still some interesting 
facts in connection with the nephridial organs of the land leech 
are detailed, and the existence of from twelve to fourteen sense- 
organs on the first ring of each complete somite is demonstrated, 
and they are homologued with the eyes, having possibly also _ 
other sense-functions. The author reserves the genus Hema- 
dipsa for the land leeches of Ceylon, India, and Japan, with 
three jaws and five inter-genitalia rings. He ascribes the genus 
to Tennant, but may it not have been formed by Baird? #. 
japonica is confined to the mountain slopes and ravines, never 
descending into the plains. It is not only a mountain leech, 
but it keeps habitually to the ground, living in moss, or under 
damp leaves andrubbish. They are most voracious, and on the 
approach of man or beast are at once on the alert. They ad- 
vance by rapid strides. They bite so gently as scarcely to 
attract attention, but the wound is deep, and the scar is more or 
less permanent. They gorge on for about 30 to 40 minutes, and 
then drop ; while sucking they become bedewed with a transparent 
liquid, which keeps them moist. Ifplaced in water, they do not 
swim but sink, and then creep out ; and while havinga decided pre- 
ference for a terrestrial life, can support life for days in water. If 
into a jar of hungry leeches a puff of breath is blown, they be- 
come immensely excited, and it will be difficult to keep them in ; 
while trying to keep back one, a dozen others will rush out. In 
a most interesting series of paragraphs Dr. Whitman traces the 
intimate relation that exists between these land and the medicinal 
leeches, the latter essentially fresh-water forms. The geo- 
graphical area of land-leeches Is mainly within the tropics, 
though in Japan they are exposed to a wide range of tempera- 
ture. //. nipponia is described as a new Japanese medicinal 
leech, well known to the Japanese, and with habits and mode 
of life just like our European leech. Leptostoma, a new genus, 
is established (p. 376) on three species of almost edentulous 
leeches, which, though having a common ancestry with Hirudo, 
were not derived from ‘it. All three species, Z. acranu- 
latum, L. edentulum, and L. pigrum, are from Tokio, and are 
fully diagnosed and beautifully figured. The segmental organs 
are shown to be sense-organs, and that from them the eyes 
have developed, so that they may be regarded as incipient eye 
spots. 
, 
NEw ELEMENT OF THE BLOOD AND ITS RELATION TO 
CoAGULATION.—In an important paper by Mr. Geo, T. Kemp 
on this subject, he comes to the conclusion that in addition to 
the red corpuscles and leucocytes the blood normally contains a 
third histological element—the ‘‘plaques.” These have been 
variously considered as young red corpuscles ; as nuclei floating 
in the blood ; as being derived from the red or the white cor- 
puscles ; as being fibrin ; and as being globular depositions pro- 
duced by cooling of the blood ; but the author proves that, 
although strong resemblances exist between the plaques and 
other histological elements of the blood, there is not yet sufficient 
evidence to establish a gerefic connection. The plaques should 
therefore, at least for the present, be regarded as independent 
elements. When the blood is drawn, the plaques break down 
almost immediately, and this is not true of any other element of 
the blood. This breaking down of the plaques seems intimately 
connected, in its time relations at least, with the clotting of the 
blood. If a good-sized drop of blood from a finger be let fail 
on a cover-glass, and as quickly as possible washed by a good 
! jet of °75 per cent. NaCl solution, and then examined under the 
