go General Notes. [January, 
of the materials at the expense of which the genital glands are 
developed. This makes it possible that, while one part of these 
embryonic materials evolves the male sex, the other may suffer 
modifications in the direction of the female. 
Reptiles —The lizards of the genus Macroscincus, which are 
not known to occur on any other spot than the desolate volcanic 
islet of Branco, three and a half miles south-west of Santa Lucia 
(Cape Verde islands) are said by M. A. Milne-Edwards to be 
exclusively vegetable feeders of exceedingly timid disposition. 
They live in holes among the loose basaltic masses which strew 
the island. The largest example obtained by the naturalist of 
the Talisman was sixty centimeters in length. 
irds.—The report of the committee for obtaining observations 
of the migrations of birds at light-houses and light-vessels aroun 
and near the British islands, contains much interesting informa- 
tion. Light-vessels moored from five to fifty miles off shore are 
most favorably placed for such observations. At Heligoland, the 
rush of migrating birds is more marked and concentrated than 
anywhere onthe English coast. The great rushes on the English 
east coast in 1883 were on September 21 and the two following 
` days, with moderate cross-currents of air blowing over the North 
sea, on October 12 and 13, and from the 27th to the 31st of the 
same month. No less than eight Greenland falcons were shot 
on the west coast of Ireland during the past year. Not a tithe 
of the enormous immigration of the autumn returns by the same 
lines in the spring. 
Mammals.—M. A. Milne-Edwards stated in 1871 that, as a 
result of an examination of the foetal development of Indris, 
Propithecus, and Lemur, he had concluded that the lemuroids 
had incontestable affinities with the herbivores. Since that epoch, 
. Milne-Edwards has examined the embryos of Microcebus, 
Galago, etc., which yielded the same results, and lastly has dis- 
sected a foetus of the aye-aye. This was found to resemble in 
every essential character those of other lemuroids, while the 
foetal membranes were those of a typical lemur. The dentition 
of the: young aye-aye is much less different from that of other 
lemurs than that of the adult, in consequence of the shedding 
and non-replacement of some of the milk-teeth. The abnormal 
characters of the species are developed as age advances. 
EMBRYOLOGY:.! 
AN OUTLINE OF A THEORY OF THE DEVELOPMENT OF THE UN- 
PAIRED FINs OF Fisnes.2—The median fins of fishes normally 
present five well-marked conditions of structure which corre- 
spond inexactly to as many stages of development, which, in typi- 
1 Edited by JOHN A. RYDER, Smithsonian Institution, Washington, Di ti 
* To appear in full in the Proceedings of the National Museum, with plates. 
