Apeil 25, 1902.] 



SCIENCE. 



663 



odal group or lower polar nucleus: the upper 

 polar nucleus migrates to the antipodal end of 

 the sac and there divides, one daughter-cell 

 remaining in that position and becoming cut 

 off by a wall across the sac, the other moving 

 back to the egg and eventually forming a con- 

 siderable mass of endosperm; fertilization 

 takes place very soon after pollination, mate- 

 rial killed within eighteen hours after pollina- 

 tion showing the embryo in a two-celled stage ; 

 in addition to the ordinary development of a 

 single embryo, polyembryony may occur, as in 

 Erythronium and Tulipa, by the division of 

 the suspensor cell to form an extensive embryo- 

 genie mass of tissue. 0. L. Shear, of the De- 

 partment of Agriculture, discusses generic 

 nomenclature, bringing up the difficulties con- 

 nected with determining generic names among 

 certain fungi. He does not offer a set of rules, 

 but reaches the conviction that the so-called 

 'type-method' is both desirable and practicable. 

 He urges the importance of selecting a start- 

 ing point for genera, definite provision being 

 made for the treatment of genera having no 

 binomial species referred to them at the time 

 of their original description. W. W. Ashe, of 

 Ealeigh, North Carolina, describes new species 

 of FraxinuSj Tilia and Crataegus; while New- 

 ton B. Pierce, of the Department of Agricul- 

 ture, describes as a new species (Alternaria 

 citri) the fungus disease of navel oranges that 

 has attracted attention in California for the 

 past eight or ten years, and which is popularly 

 known as 'black rot of oranges.' 



In Popular Astronomy for April, Percival 

 Lowell, of Boston, gives an 'Explanation of 

 the Supposed Signals from Mars of December 

 Y and 8, 1900.' Many will recall that it was 

 then reported that Mars had been signaling 

 the earth; that lights had suddenly shone out 

 brightly, and then vanished. The explanation 

 is that this misrepresentation came from a 

 telegram sent to Mr. Lowell as to a projection 

 then observed on the surface of Mars,, similar 

 to those more often seen on the moon. From 

 a study of the projections on Mars, the writer 

 believes that these are due to clouds floating 

 in the air rather than to mountains on the 

 surface. 



George C. Comstock writes of the 'Motion 

 of Comets when far from the Sun.' He 

 speaks of comets as they are commonly con- 

 sidered, as mere visitors who come from the 

 region of the fixed stars, and after a temporary 

 sojourn here return. An interesting popular 

 article on the 'Zodiacal Light' is written 

 by Arthur K. Bartlett, of Battle Creek. This 

 light which is seen at this time in the year on 

 any clear moonless night after sunset might 

 be mistaken for the aurora borealis by those 

 unacquainted with astronomy, were it not for 

 its position and form. Its form is that of a 

 cone or pyramid having its top rounded, and 

 its base directed toward the sun, and with a 

 light like that of the Milky Way. Mr. Bart- 

 lett speaks of the various theories to which 

 this illumination has been, and is, attributed, 

 inclining towards the one most generally ac- 

 cepted, though not established, viz., that of 

 meteors combining in unknown millions, re- 

 flecting to our eyes the peculiar light in ques- 

 tion, borrowed from the sun, aroimd which 

 they revolve probably as do the planets. The 

 usual amount of space is given to ciu-rent 

 news and notes of comets, asteroids, planets 

 and variable stars, and to various short 

 articles. 



SOCIETIES AND ACADEMIES. 



NATIONAL ACADEMY OF SCIENCES. 



The annual stated session of the Academy 

 was held in Washington, D. C, April 15 to 17, 

 inclusive. 



President Alexander Agassiz presided at the 

 meetings, which were attended by the follow- 

 ing members: Messrs. Abbe, Abbot, Agassiz, 

 Allen, Becker, Billings, Boas, Boss, Brewer, 

 Brooks, Cattell, C. P. Chandler, S. C. Chand- 

 ler, Chittenden, 0. B. Comstock, Crafts, Dall, 

 Enunons, Farlow, Gilbert, Gill, Hague, Hall, 

 G. W. Hill, Langley, Minot, S. W. Mitchell, 

 Moore, Morley, Newcomb, Nichols, Osborn. 

 Peirce, Penfield, Pickering, Prudden, Remsen, 

 Richards, Sellers, E. F. Smith, Walcott, 

 Welch, White, and Woodward. 



Most of the time during the sessions was 

 devoted to routine business, hearing reports 

 from the ofiicers of the Academy, chairmen of 



