December 16, 1922] 



NA TURE 



by a pore in the mid-dorsal line of the fourteenth 

 somite. The gut of Trematobdella, as described by 

 Blanchard, also opens by a pore in the mid-dorsal 

 line, and in Horst's Nephelis dubia there are two 

 slender passages from the gut to the ventral surface 

 where they open to the exterior. 



Philippine Cattle Round-worm. — B. Schwartz 

 records (Philippine Journ. Sci. xx. No. 6, 1022) 

 observations on the life-history of Ascaris vitolorum, 

 a parasite of cattle and of water-buffaloes in the 

 Philippine Islands. The eggs develop rapidly — but 

 it exposed to the heat of the tropical sun are quickly 

 destroyed — and contain larvae after about twelve 

 days. Such eggs hatch in the intestine and the larvae 

 migrate via the liver and lungs back to the alimentary 

 canal, as in the common round-worm of man, Ascaris 

 lumbricoides, but appear to have a greater tendency 

 than in the latter species to linger in the liver. 



Distribution of Oligoch.t.ta in the Antarctic. 

 — Two further parts of vol. vi. of the Australian 

 Antarctic Expedition are contributed bv Prof. W. B. 

 Benham — Part 4 on the Oligochasta of Macquarie 

 Island and Part 5 on the Unarmed Gephyrea. In 

 the former four oligochaetes are recorded — two 

 species of Marionina, one Lumbricillus, and one 

 Microscolex (Notiodrilus). In connexion with this 

 last, Prof. Benham discusses the views that have 

 been advanced to account for the present distribution 

 of Oligochaeta on the sub-Antarctic islands and 

 concludes that this cannot be accounted for by 

 polyphyly, floating rafts, carriage by birds, or by 

 drifting seaweeds, and he is led back to the view, 

 first put forward by Beddard in 1891, that the various 

 islands and southern lands were once connected by 

 land bridges. He believes that the former occurrence 

 of chains of islands would suffice to explain the 

 distribution of oligochaetes, for the cocoons of these 

 worms might then have been distributed on the 

 feet of birds, and the pelagic larva? of some of the 

 littoral animals might have been able to survive 

 for the short time necessary to pass across the inter- 

 vening seas. He puts the origin of the Oligochaeta 

 " somewhere in the early Mesozoic epoch." 



Fungal Diseases of Rice. — In the annual report 

 of the Department of Agriculture of the Uganda 

 Protectorate special attention is directed to local 

 fungal diseases of rice. Early failures in the rice 

 crop used to be attributed to unsuitable environ- 

 mental conditions, but it is noteworthy that the 

 symptoms of " blast " disease resemble the effect 

 of drought and poor soil. This well-known disease, 

 caused by Piricularia oryzce, is reported for the first 

 time in Africa. The disease appears to be wide- 

 spread, not one of the plots examined being com- 

 pletely free. Both leaves and stems are affected, 

 and when the latter are attacked at both nodes and 

 internodes the plants may break down and the whole 

 plot collapse entirely in bad cases. The ears are 

 sometimes normal, but if attacked the grains are 

 empty or only half filled. At no time has any 

 diseased condition of the roots been observed. 

 " Blast " appears to be the only major disease of 

 rice in Uganda, but in one instance Gibberella sau- 

 binetii, a fungus with a bad record, has occurred. 

 The supposed conidial stage of this fungus, a species 

 of Fusarium, has not been proved to be connected 

 with the Gibberella, and it is not pathogenic to 

 wheat, rice or maize, on all of which it was found in 

 the country. 



Prairie Vegetation in Illinois. — A paper by 

 Homer C. Sampson under this title, published as 

 Article 16, in vol. 13 of the Natural History Survey 



NO. 2772, VOL. I IOj 



of the State of Illinois, illustrates how American 

 ecologists are attempting to record their main natural 

 egetation features before these are too much modified 

 by man's activities. Sampson recognises the great 

 importance of climate in determining the " centre of 

 distribution " of the great prairie formation, which 

 coincides roughlj m its distribution with the area 

 where the ratio of rainfall to evaporation lies between 

 60 and 80 per cent. As the prairie is met with 

 farther from its natural centre of distribution, its 

 stability becomes increasingly less so that it dis- 

 appears before various edaphic and biotic influences. 

 Sampson describes the origin of the prairie from the 

 swamps and drier upland regions left at the close of 

 the last glacial period. On these two soil types two 

 different series of plant associations have followed, 

 hydrophyte and xerophyte respectively in character, 

 but both have ended in the prairie zone in the same 

 association, dominated by Andropogou furcatum, 

 the tall blue stem grass. Very striking must have 

 been the appearance of the wide-rolling plains, 

 clothed with tins grass growing to a height of 10- 

 12 feet, so that the earlier settlers could follow the 

 movements of their cattle only by climbing to elevated 

 ground and noting the agitation in the vast plains of 

 grass. The author is to 'tie congratulated on one 

 unusual feature which terminates a memoir which is 

 throughout admirably clear and concise. This is t he- 

 bold attempt made to summarise the chief features 

 of prairie vegetation in non-technical language so 

 that the general public may lear., the results of the 

 study of one of the great natural assets of the state. 

 This" public should be interested in the author's 

 statements as to the relative want of success that 

 attends efforts to bring natural forest under cultiva- 

 tion as compared with the results of cultivation of 

 prairie land which is normally richer in humus and 

 less leached of its inorganic constituents. 



Weather in the Wesi Indies. — Monthly and 

 annual reports of the West Indies and Caribbean 

 Weather Service have reached us for 1921 and a 

 large part of 192 2. The publication is carried out 

 by Mr. Oliver L. Fassig, meteorologist in charge, at 

 San Juan, Porto Rico, the service being in co- 

 operation with the governments of the islands of 

 the West Indies and of the adjacent coasts of Central 

 and South America, under the controlling influence 

 of the U.S. Weather Bureau. Daily rainfall returns 

 are given from about 350 stations throughout the 

 year 192 1, and from more than 400 stations in the 

 early months of 1922. In the latter year monthly 

 mean and extreme temperatures are added. For 

 each month the mean rainfall for the entire section 

 is given based upon the reports from all stations 

 observing, and usually a comparison 1- made with 

 the normal. In 192 1 the mean precipitation for 

 tli. entire area was lightest during the month of 

 April with .1 mean of 2-11 in. and a mean frequency 

 of 8 days ; the month of heaviest rainfall was 

 October with 7-57 in. which fell on 16 days. The 

 mean annual fall for the entire area was 54-32 in., 

 and the mean number of days with rain was 144. 

 In Jamaica the annual extremes at different stations 

 ranged from 26 in. to 199 in., and in Trinidad from 

 60 in. to 156 in., the annual totals differing greatly, 

 due to the' varying topography. Observations are 

 recorded of evaporation, water temperature, and 

 earthquakes. The occurrence and movements of 

 tropical storms arc stated, warning of each storm 

 being given by the U.S. Weather Bureau I 



wlupment of the reports is evident, and 

 the valui ita will in tins way be further 



ed. 



