LAGH(M.\T. 29 



a census of the plat\t popul;ilioi\. Here the luuuher of iiuiividuals, as well 

 as their size, showed that the tnoistua^ ivlations were good as compared 

 with those of the plaiti. Oti an area 16 nieters sqttaa^ 433 \Wm^ ix^rennials 

 wcR^ found, mainly of the followinv; species: Acanthyllis tragaianthotdf's, 

 Asparai^us sf>inoso, Di-vcrra scopan'u, and /.oUiko/en'a spinosa. The most 

 nun^erous, ZoUifcofi'tia, was n^prescnted by 00 ituhndnals. The .t:eneral 

 character of the habitat and the plants is sulVicicntly well slunvn ii\ lii:. 8 

 and does not need further mention in this place. 



KFFKCTS OF GRAZING ON VKOKTATION NKAR t AC.HOl'AT. 



It is generally rcaigi\ized that a potent innuence is exerted by man. 

 and the lower atiitnals, in shapitig the llora of at\ arid tvgion, uoi only ns 

 regards the kind and number of phmts, but also as conctu-ns certain of the 

 leading characteristics of the plants theinsclvcs. The action is largely such 

 as brings about a survival of the "useless" fonns, so that we do not know, 

 from the plants we nieet in the desert to-day. how many ov what kinds of 

 plants it might suj^port . It also may be (nic ( hat no desert shows the mod- 

 ifying effects of the causes suggested moix< than the northern Sahara. 



The ga7.clle {Cazclla dorcas) is the leadit\g wild anitnal prc>-ing upon the 

 desert plants in the northern Sahara. It is fivqucntly scci\ by the traveler 

 to-day and was present \\\ large numbers no lotigcr ago than 50 years t,Tris- 

 tram). It is said by the :\rabs to feed on the fresh shoots and leaves of 

 many species of shrubs and trees, especially the betoui\i {risiacia atUintica). 

 as well as on the annual vegetation for the ivlalively short periovl when it 

 is to be had. Other .species of gazelle. ac(.vrding to Tristram, range farther 

 ti> the sonlli. thlicr Iicrbivorous .luiiu.ils (>!" the rej;ion aic hatvs, antelope, 

 moutllon, and bubalc. The nunilllon. at the time of Tristratn's visit, was 

 "far from unconiiiuM\ throughout the whole of the mountain districts, 

 whether wooded or bare." but tlu^ bubalc. "the wildest of the wild g.une 

 of North Africa," appears not to go north of the Oucd Rirh. while its home 

 is farther south. It is impossible [o know the tmmbcr o( wild anitnals 

 subsisting on native desert vegetation, but the list given, which tnight be 

 extctulcd. suggests that it is by no means small. Although the population 

 o{ wild herbivorous animals is at pivsent considerable, it. was probably 

 much greater a few years ago. the decivasc being duo, as Tristram says, 

 not so nuich to the gtvatly increased population as to the nunv etVicicnt 

 weapons used by tlu^ Arabs '\\\ hunting,* 



* Tri.'5tniin remarks tluit it " scen\s titat (l\o iar^or wilil animals liavo boon rapidly 

 dooroasinj; in nnmlnMs an^l arc in prvK'oss of spoi^lv oxtinotion. l>r. Sliaw, 150 voars 

 sinoo, oiuinuMiitos in l\is tr.ivols . . , tivc spooios o{ nmiinants, whioli i't'v>m liis tlosorip- 

 tions must bo M»o bnbalp, tlio aoiulavi or wild slirop, ll)o !uiil.»x, and tlio jjar.t^llo. as wrll 

 ns tl»o sta^:. . . . As tlio poptilati(>n lias not iiu-roasod, Inil rathor rotn^^;railoil. wo o.m 

 only snnniso tl»i\l tlio subslitnlion of (ho Hint anil stool yj\\\ (ov tlio m.ilohlook of tlio 

 lUHhniin . . . lias boon fatal in its tosults to all iai'Kor >;anio." It may bo rom.ukod tliat 

 tlio I'^ronoli iniposo snoli tost riot ions on tlio Arab as to>:arils Mio oliaraotor of tlio jjnns lio 

 may uso lonly Hio arniv ami oortain olVioials of tlio ^jovornmont omployiii); iiuHtorn 

 anus) (li.il for tlio ioi;ii'n visilod I'l isl ram's dcsoription holds fairly woll for to-day. 



