SCIENTIFIC SUMMARY. 
455 
abnormal deviations result from the left region of the vascular area being 
more developed than the right and he says, that if the experiments can 
bring about this increased development, he can produce inversion artificially. 
The method he gives for the production of this phenomenon in the hen- 
egg, is simple enough. Place the eggs so that their long axis is obliquely 
situate in relation to the axis of the heating tubes of the apparatus, and let 
the pointed end be always higher than the round one. 
The Formation of the Ovule . — At a recent meeting of the Academy of 
Sciences of Paris, M. Perez presented a paper in which he advanced certain 
views on this point. M. Davaine now {Comptes Rendus, August 24) 
claims the priority, and quotes passages from his Memoire sur rAnguillule 
de laNielle,” which show very clearly that his claim is a just one. 
Arterial Capillaries in Insects. — This much-debated point seems to be 
decided in the affirmative by the researches of M. Jules Kiinckel, who states 
that he has convinced himself of the existence of a series of arterial capil- 
laries in insects. These, he says, divide and ramify in the finest divisions, not 
only in the muscles, but in the various organs of the body. Generally the 
blood examined by transmitted light presents a reddish colour which 
renders the capillaries distinct. When the blood leaves the vessels, as he 
has often seen it do, they lose all their colour. It is easy to see the trachea, 
but very difficult to distinguish the capillaries, their walls are so thin and trans- 
parent. The difficulties of observation,” says M. Kiinckel, ^^are very great. 
It is necessary to take a bundle of muscular fibre from the living animal, and 
place it at once beneath the microscope ] then, under favourable circum- 
stances, the blood may be seen flowing rapidly from the capillaries.” For 
these researches a high magnifying power is necessary, and M. Kiinckel re- 
commends the employment of immersion lenses. The capillaries would 
seem, from the author’s statement, either to be formed by or to be adherent 
to the outer wall of the trachea ; the inner wall does not proceed far into 
the tissue, but ends as a cut de sac, while the outer one is continued on to 
constitute the capillaries. — Comptes Rendus, July 27. 
The Retina of the Hedgehog.— lo. a paper read before the Koyal Society, 
Mr. J. W. Hulke stated that this retina is very remarkable from the fact that 
all the arteries and veins lie upon the inner surface of the membrana limitans 
interna retinse, in intimate relation with the membrana hyaloidea ; while 
capillaries only traverse the limitans, receiving a sheath from it, and pene- 
trate the inner layers of the retina. The hedgehog’s retina is in this respect 
a link between the non-vascular retina of fish, amphibia, reptiles and birds, 
and the vascular retinse of most mammals. 
The Avine Fauna of Madagascar and the neighbouring Islands. — The last 
number of the Proceedings of the Royal Society contains a very interestiug 
communication from Messrs. A. and E. Kewton on the osteology of the 
solitaire. Besides discussing the osteological part of their problem, the 
authors make the following highly suggestive remarks : — Of the other terres- 
trial members of the avifauna of Rodriguez but few now remain. A small 
finch and a warbler, both endemic (the first belonging to a group almost 
entirely confined to Madagascar and its satellites, the second to a genus ex- 
t ending from Africa to Australia), are the only two land-birds of its original 
fauna now known to exist. The guinea-fowl and love-bird have in all pro- 
