80 th^t baboons se&rch for end ert Lithops n^'jauo-truncetella , so the t 

 they, 6t any rate, have learned hoiv to detect it, in spicte of 

 the' feet that it is e species that so closely'' resembles" the stones 

 it .'^rov.-s aaonjfr as to be easily overlooked. Yet one cannot over- 

 look the fact that the ordinary non-botanical person as I have 

 reGor':^ed in The '^-ardeners ' Chronicle, vol. L]^, p. 250, and vol. 

 IXXT, p. 44. 



Even wh6n in flov/er, some of these mimetic species, I eiL 

 informed by more than one South African observer, are practically 

 indistinguishable from their surroundinj?s at a short distance, 

 ^nv"" "-hen out of flov^er and at rest, they are so inconspicuous thL;t 

 0*^6 correspondent, vnritinr- of mimetic si^ecies belong to other £'en- 

 er? t^ian lithors, vrites of then, vv'hen in a restjjig condition s 

 "I cannot find them, I can't think where they all get to." So 

 that if animals and bird?, ■ spite of their having keener eye- 

 sight and instincts than nan, are, after all, only comparable v/ith 

 the ordinar:?" non-bot'-nicpl observer ^nc" not vith the botanical col- 

 lector, then there can be no dou' ' icry v.'ould protect the 

 T^"'^nts. Biit can vre assnine that in tlie c ,jei passed enimals and bir- 

 :'", driven ^-' '^"n^-r, have not le'^rn^d how to use their keen eyes 

 ■ •-' ^ "-'sting- ■ ^e mimetic rom their surroundings, even 

 as the keen-eye.: ootanist has aone'- -*t present, it seeiiis to me, 

 th^ t fy'i~ !^i;'^*-ct of mimicrv has not been so cle'rl"'' solved as 

 some r jlieve. 



iinu t.iere is f^nother problem connected : :' ' " ;^enu3 



I-lthops (and other re-pr- th-t "-along to the 1 -oup c-lled 



'''Windowed Plants"), ' ' re are seid to grov>? burled e 



'^roimd •""ith only the t O" oi \.inuovfed part of the leaves above ^iie 

 soil, o:^ v^hic'- the accepted solution is no-f- r^^^if^ r sufficient mc. 

 satisfactory explanation, I think. I ha\ ' rticular. 



an illustration of the structure and zriode u - of thii^ ^.juL^t; 



i'-" The ^'■ar-'ieners • Chronicle, 1921, vol. L'^-, . : , f. 11^, and 



'tional details 0:^* the same su'^'^'ect be fc --iss 



- . -'■ -T.ten in the I'utc' --■ • -qt^^ Juco..lentp, l.::.^, vol. 'H, 

 '" . l-l~. '^'a rbove-ruc-- . i'^'i r . .''].) is repro ■"::ced here, end 



?hws hCT- o''lorophyll-l^yer ( . ' ^1 is co.;. to the 



'-rt of the fissure of t " ost u ' ein^ ui.. ._ - 



_, tor (Fi.-. 41 D) be-'r,r' f ich i jtitute 



U-. 



-11 . 



^. — Lithors (Mesembr:- 

 I-es!! iei 



'"lie accepted explanation of the purpose C"^ thi ::;:ent 

 s alrepdy deta-'led at th " oe quoted, is ' jro- 



phyll from being injured by tnc intensity of t:ie lie-.t ii- i^o^ 

 native region. But continued observations of the beh^;v* :ur of this 

 and other genera of '''.Vindo^wed Tlants" having the - ' struc- 



ture, h^s cau'sed m.e to flter my opinion. For, as £rov;n by x^yself , 

 t;-o3e ^i_^^+-r- ro not like be'"" --r-io^ i-^ -i-v -. r.-.l^; 5^ "l- '^ted so, 

 .- - *irs" -rowth -^h-r t t^ 



bove it, an:! £ plant of " iou to — . r^.o^ulo]^. 



■ -^■^n' ----1^ ifter be foun'^ ^,. '"'.v tba ~'.m-F, -'0 es __ . _.. ) 

 -' " " --nted buried in send, --- ^ , ,, arloth's 

 si^l-- ' book The ^lorr- of '■ "■ice, vol. -^, ]'■. -i07, t. 52, 



