December 29, 192 1] 



NATURE 



5^5 



Agriculture in the Maxyut District, West of Alexandria.^ 



THE coast district lying to the west of Alexandria 

 and known as Mareotis was well known in 

 Graeco-Roman times and for long after for its gardens 

 and vineyards, and even down to the time of the 

 Arab historian Makrisi figs and grapes from there 

 were sold in Alexandria. For several centuries, how- 

 ever, it has been a barren waste except for small 

 patches of barley raised by the nomad Arabs in the 

 more-favoured spots when the winter rains are plenti- 

 ful. In the report under notice an account is given 

 of an examination made by the Geological Survey 

 and the Ministry- of Agriculture of Egypt to deter- 

 mine whether the area offered any prospect of a 

 remunerative return from dry farming or from irriga- 

 tion by the extension of the westernmost canal of the 

 delta system, the Nubariya. 



The district which the report covers is a belt about 

 15 km. wide on the shore of the Mediterranean, and 

 it extends from Alexandria to a point about loo km. 

 to the westward. Starting from the sea-shore, there 

 is, first, a series of white dunes formed of small 

 rounded oolitic grains which, by the action of the 

 winter rains, unite to form masses of more compact 

 rock. Behind these dunes, which do not exceed 

 10 metres in height, is a narrow depression which 

 is of considerable fertility. Farther inland is a higher 

 limestone ridge, where numerous ruins indicate that 

 it was once well populated. The main depression lies 

 behind this ridge, and is about 4 km. wide; figs and 

 barley are cultivated on the slopes on either side of 

 the saline marsh which occupies the central portion 

 of the depression. 



The rainfall, which is limited to the months 

 October-March, varies considerably from year to year, 

 ranging from 100-300 mm., and if rain is scant}- in 

 November the barley, which is sown as soon as the 

 October rains occur, may yield a very poor crop. 



1 " The Soils ami Water Supnly of the Maryut Diitrict. West of 

 Alexandria." By Dr. W. K. Hume and F. Hughes. (Cairo : Government 

 Press, 1921.) 



Full details are given of the physical character of 

 the soil in many parts of the district and at various 

 depths, but what controls all extension of vegetation 

 is the presence of intensely saline water at or near 

 sea-level. On account of this the cultivation of any 

 considerable area is difficult, and the Arabs are able 

 to utilise only the more favoured spots to raise their 

 crops. While it seems probable that about 12,000 acres 

 might be brought under cultivation by the extension 

 of the Nubariya Canal, parts of this area would be 

 too stony for satisf acton.- cultivation. Generally 

 speaking, a more detailed study of this part, together 

 with more extended contoured surveys, will be neces- 

 sarv before any decision can be reached as to the 

 desirability of irrigation on this part of the desert 

 margin. 



A trial of dry farming was made in the MarAut 

 district in the seasons of 1917-18 and 1918-19, but lack 

 of rain in November seriously damaged the crops. 

 The conclusion was reached that such methods are 

 not likelv to be successful owing to the variable 

 character of the rainfall and the patchy nature of 

 good soil. 



By sinking wells and utilising the winter rainfall 

 fruit-gardens could probably be developed, and this 

 was the principal form of cultivation in ancient times. 

 ! Over a large area numerous artificial mounds enclose 

 rectangular areas (}iarni), which were certainly at one 

 time gardens. These were watered from wells and 

 from the run-off after winter rains had fallen on the 

 enclosed land and some of the water had been con- 

 served in the central area. 



Though the investigation has not led to a prospect 

 of a large extension of Egypt's cultivable area, it has 

 placed our knowledge of the Marvut district on a firm 

 basis, and has shown what developments there are 

 possible. The report is well illustrated, by maps and 

 photographs which show the character of this coast 

 region. 



Fisheries Biology.^ 



OOME notable papers on marine biology of interest 

 •^ in fishery investigations are contained in the last 

 number of the Journal of the Marine Biological Asso- 

 ciation. Mr. E. Ford takes up a matter that has 

 hitherto received very little attention — the life-history 

 of the dogfishes. Now that these animals are being 

 utilised as human food (particularly the spur-dog, 

 which enters the markets as " flake ") their biology 

 has utilitarian value, and this paper is, therefore, of 

 much interest. The author deals mainly with phases 

 in the reproductive cycles of the common species (the 

 spur-dog, the rough-dog, the nurse-hound, and the 

 sweet-william). The spur-dog and nurse-hound are 

 viviparous, and the prolonged period of incubation in 

 iitero deduced by Mr. Ford will come as a surprise to 

 most readers ; this, in the case of the spur-dog, may 

 extend to twenty-five months. Biologically, the re- 

 productive processes in the dogfishes are of immense 1 

 interest, and one may hope that Mr. Ford may con- 

 tinue his investigations and give us much needed 

 information as to the natural histon." and physiology j 

 of these animals. i 



Dr. Marie Lebour continues her well-known work 

 n the food of baby fish. Quite lately this subject has I 

 become one of extraordinan,- importance in fishen." , 

 investigation, particularly in view of the implications ! 



1 Journal of the Marine Biological Association, vol. 12, No. ^, Plymouth- 

 Sepiember, 1931. 



NO. 2722. VOL. 108] 



of Dr. Johan Hjort's work on the cod and herring. 

 That there are natural "crises" in the conditions 

 that rule the abundance of sea-fishes is now estab- 

 lished, and upon these crises — far more, perhaps, than 

 upon anv reasonable variations in the intensity of 

 fishing — depend the quantities of marketable fish 

 present in the sea in any year. There is a short 

 period in the life of the ordinan.- fish when, its supply 

 of food-yolk being exhausted, suitable pelagic 

 organisms must be found and eaten. The periods of 

 multiplication of the latter are variable, to soine 

 extent, from year to year, and so are the spawning 

 periods of the fishes. In some years, therefore, 

 abundant food mav be forthcoming just at the time 

 of disappearance of the larval fishes' yolk-sac, but in 

 other years this food may fail, its production occurring 

 well before or after the time when the larval fish 

 transformation occurs in greatest degree. A heavy 

 mortality,- in the baby fishes must be followed, two 

 or three years later, by a scarcity* of the adults, and 

 vice versa. 



For a proper treatment of this problem we require 

 to know (i) the kinds of food eaten bv larval and fx)st- 

 lar\-al fishes, (2) the periods of maximum production 

 of the food, and (3) the maximum spawning periods 

 of the fishes. The first Question is being investigated 

 bv Dr. Lebour with much success, and in this paper 

 she deals with the food of baby herrings, sf>rats, and 



