I\rarch 31, 1887] 



NA TURE 



521 



movement on ■x slope of 4 to 5 degrees is 5 23 mm. per 

 hour, or I25-I mm. per day. Hcrr Seeland left the pegs 

 and stones where they were, and laid down other marks for 

 future measurements. 



I.IEUT. WissMAN.v, who has already done so much good 

 exploring v.ork in the Congo region, started in November la.st on 

 a fresh expedition, from Luluaburg, the station on the River 

 Lulua, an allluent of the Kasai. Wissmann goes first to the 

 junction of the Lubi wiih the Sankuru, tlie great southern 

 tributary of the Congo. Thence he will endeavour to push 

 northwards and explore the unknown country in which the 

 lulongo, the Chuapa, am', the Lomami take their sources. He 

 will then seek to reach Nyangwe, when he will m.ike up his 

 mind either to proceed northwards to the Muta Nzigc, or south 

 to explore the Lanji, the Lukuga, and the Upper I^ualaba. 



The paper at Monday's meeting of the Royal Geographical 

 Society was by Mr. J. T. Wills, on the region between the Nile 

 and the Congo. It was a summary of all that we know of the 

 region, and places us in a position to appreciate the value of any 

 exploring work which may be done by .Mr. Stanley. It deals 

 succinctly with all recent explorations of the Upper Nile region, 

 and with the intervening country between that and the Middle 

 Congo. The valuable work of Dr. Junker, as well as that of 

 Emin Pasha, receives special prominence. Mr. Wills rightly 

 dismisses the Shari hypothesis in connexion with the Welle- 

 Makua, and insists on the identity of the Makua and Mobangi. 

 The Mobangi is known to be a waterway not inferior to the main 

 Congo for practical purposes ; deep, never less than 600 yards 

 wide, even in February, when the Kuta Makua certainly (and it 

 loo apparently) is at its lowest level ; and navigable at all times 

 from Stanley Pool 650 miles thence straight north-north east to 

 lat. 4° 20' N. beyond the limit which the Congo State, by private 

 treaty with Germany, has placed to its future "sphere of opera- 

 lions," and beyond the limits which the French will probably 

 occupy if they win in their dispute with the Congo State .as to 

 which of the two shall not operate in the Mobangi b.asin. It is 

 then found to turn sharply to the east, (lowing from the east 

 through a gap it has cut in a line of quartz and red clay hills 

 1000 feet high, hills which may be continuation of the hilly 

 watershed between the Makua at Ali Kobo and the sources of 

 the Xgala. One would expects rapids at such a place, but there 

 is only a good current and some awkward rocks ; after recon- 

 noitcring in a boat, Mr. Grenfell got the /'(af^ through easily, in 

 February. Where we know the Kuta Makua next, they are 

 placid and colossal ; the .Shinko at Marra is still 90 yards wide, 

 20 to 35 feet deep in October, and only 1980 feet above the sea. 

 The average fall thence to Stanley Pool (1070 feet above the sea) 

 is by this only some 9 inches to tlie mile, and the main Congo 

 appears to nearly maintain this slope up to Bangala, beyond the 

 Mobangi mouth. 



BIOLOGICAL NOTES 

 iNjtjRious Fungi in' California. — The following facts 

 recorded by Prof. W. G. Farlow are not without interest in 

 Europe: Nicoliana g/aiua, abundant in Mexico, attracts atten- 

 tion by its pleasing foliage and graceful habit ; it is a native of 

 Buenos Ayres, but is acclimatised in Mexico. Within the last 

 few years it has escaped from cultivation in California, and is 

 now a common weed by the roadsides. At San Diego Prof. 

 Farlow noticed that the leaves were badly attacked by a fungus 

 which formed large, grayish-black spots on both sides of the 

 leaves. Examination proved it to be Pcrotiospora hyoscyami, 

 De liary, which was first found on Hyoscyamus tiif;er, L. , in 

 Europe, where it does not .appear to be at all common. Since 

 it is well known that the species of Peronospora attack different 

 species of flowering plants which belong to the same natural 

 order, it is much to be feared that the disease which now attacks 

 N. glaiica may sooner or later extend to the cultivated tobacco, 

 which belongs to the same genus. If this were to happen, the 

 injury to the tobacco would be very great, since, by causing large 

 spots on the leaves to rot, they would become worthless for 

 manufacturing purposes. The question of the possible spread of 

 the disease is one of importance, for it would be a very serious 

 thing if it were to reach the great tobacco-growing regions of 

 Slates like Virginia. 



Fertilisation of Cassia marilandica. — The relation of 

 insects to flowers continues to be a question of profound interest, 



but Mr. Meehan thinks that the dependence of a plant on insect 

 aid is rather an indication that, instead of any material aid toils 

 race being gained, its race is nearly run ; he thinks that the 

 opposite assumption has been an injury to the study of the 

 main questions on fertilisation, and that the statements of Darwin 

 and Asa Gray do not warrant the gener.ahsalions that have been 

 drawn from them. In C. marilandica the phenomena attending 

 pollen-formation are curious and apparently little known. The 

 stamens are arranged in different sets. There are three beneath 

 the pistil— the two lateral ones are very strong and equal the 

 pistil in length, the central one immediately beneath the pistil is 

 as long as those on each side, but more slender. Immediately 

 above the pistil are four stamens, with short stout filaments, the 

 anthers being perfectly formed and nearly as long as in the lower 

 set. Above are three petaloid stamens. All the stamens have 

 long black anthers, full of pollen, but which seems never to burst 

 the anther cases. The only opening is at the apex, and this 

 opening is covered by a membrane — never opening except by 

 insect agency. As soon as the flower expands it is freely visited 

 by humble-bees, and, as their loaded thighs evidence, for the 

 pollen. To collect this they alight on the anthers of the long 

 and lower stamens, as on a pl.itform, make an opening in the 

 apex of each of the four shorter ones, and then rifle them of their 

 contents. A mass of plants containing eighty-eight flower-stems 

 was watched on July 30, and the same lot for an hour on August 6, 

 but no attempt was seen to be made by the bees to get the pollen 

 from the longer anthers, or to use them in any way but as a plat- 

 form. It would be very difficult for the bees to stand anywhere 

 so as to have power to pierce the apical membranes of the longer 

 stamens. When the flowers matured, and the anthers were 

 ready to fall, they were examined, the four short ones were empty 

 sacs, the three lower ones were full of pollen. These latter 

 served no visible object to the flower or its insect visitors. 

 While, however, no pollen could be detected on the stigmatic 

 surfaces, still three out of every twelve flowers yielded a pod, 

 and panicles of flowers covered so as to prevent egress of insects, 

 neither produced fruit nor did a single anther open at its apex. 

 In this case it would appear as if the fertilisation depended on 

 the accident of the extracted pollen escaping from the insect to 

 the stigma, and yet to an ordinary observer this plant would seem 

 one specially arranged for cross-fertilisation. (Proc. Acad. Nat. 

 Sci. Phil. l886, p. 314.) 



Variations in the Nerve-Supply of the Lumbricales 

 Muscles in the Hand and Foot, with some Observa- 

 tions o.x the Perforating Fle.'CORS. — Dr. H. St. John 

 Brooks has lately investigated the subject of the varieties in the 

 nerve-supply of the lumbricales. He finds — (i) Discrepancies 

 in the statements of English and Continental anatomists. All 

 these writers appear to be in error about the normal or com- 

 monest arrangement of the nerves to these muscles in the foot, and 

 they appear never to have noticed a double supply to the third 

 lumbrical in the hand. (2) Varieties of innervation that the 

 author has observed in man, with an account of the nerve- 

 supply in the orang, gibbon, and macaque monkey. He has 

 discovered nerves entering the deep surface of the second (or 

 indicial) lumbrical muscle in both hand and foot ; these nerves, 

 he believes, have never before been described : the latter, how- 

 ever, has been seen by Prof. D. J. Cunningham in the foot of a 

 negro, and is recorded by him in his notes (as yet unpublished) 

 of the anatomy of the negro foot. The following statistical 

 table is compiled from the author's notes : — 



7'alile of Vai ialions in the Innervation of Lumbrical Muscles 

 Hand 



Cases 

 First and second by median ; third and fourth by deep 



ulnar ... ... ... ... ... ... ... 9 



Third by median and deep ulnar (others as before) ... 6 



Second and third by deep ulnar ... ... ... ... I 



First, second, and third by median (deep dissection not 



carried out) . ... ... ... ... ... ... 2 



Total 18 



Foot 



First by internal plantar ; second, third, and fourth by 



deep external plantar ... ... ... ... ... 8 



In the orang, gibbon, and macaque, the second lumbrical of the- 

 foot was supplied as in the above table. (3) Prof Cunningham 

 (Challenger Reports, vol. xvi.) has shown that, in Thylacinus 



