IIkimn-Ai.i.KM AMI! V.KH\JiH\i~-StuH^ nf Verneuilina polyttmphn. 17i 



niiicrnblo intormt wluni wu linil |>ii)iImiIim1 ilicm. With • view to mrryinit 

 llio matter further, wc had made for un s fiiic muhI — »liiii«'. n tnuii— hj llie 

 oniahing of rough gems, inoluiJing ruby, fuip|ihirv, omorald, topaz, olivine. 

 |H<ndi>t, t;nrnot, t'>uriiialiiii% •ml nthfrn. Tliin wm hhkxI «ritli >'0 |H'r r«*nt. 

 • >f ordinary naiul atul n luiinU'r of living ii|K*ciiiiftiit of T /N>/ys/ii'/>A>i, wajihr<l 

 from wwhIs nt the Mixmi Kcvf ^a grtuip of ruck* osponctl at low tide about 

 a iiiilo Houth of the |M>inl of Svlaoy Kill, Suhmx), were placed with thia 

 gt'innaiMl in two tjinkit. one litlml with iionnal M-n-wnler, an<l ihc odirr Tillrd 

 with (M>u water ruudcrvd hy]>urt<>nic by doubling' thi- noniial lime cuntcht by 

 the addition of 2*8 gr. of Chloride of Calcium [>er litre of aea- water. 



The linil attempt proved a failure. Owing lu the faet that the gems liad 

 Uvn (tuMkhI with *\w\ rollem, the itand contained no much iron that all lift* 

 in the tAiiktt died. The nand wait removed. Im>iIo<I in acid to eliminate thi- 

 iron, wa«he<t and dric<l, and the experiment renewed. As a renult of tiie 

 wajihing.a good deal of the finer aand waa inevitably lont, but thijt iinexpcct4xl 

 factor ban in the result incn-jwed the interejil of the e.\|>erimenlii. which 

 were commcnce<l in the nprin^of 1915. The creatures were left undiiilurt«<l 

 (excepting that the ovaiMtration waa compeiiwitc<l by the addition when 

 re«|uire«l of rain-walcrj to increaao and multiply until the spring of 1910, 

 when the (onteiila of lM>th (ankft were removed, wa«hed, and examined. 

 In lM)tli taiikM the rc«ult« exceeded our aiiticii«tions. 



MoMl of the adult testa, and all the younger ones, which had been bom 

 in the tankn liad incorporated gem-sand in their testa (figs. 17, 18), and a 

 profMirtion of the creatures had utiliziil g(>m-splinteni of a niu* and shape 

 ull4-rly ili8pro{Kirtioiiate to the size of the testa, thus prtHlticing a variety 

 which preseiitu a striking contrast to the iionual ly|>e, which, as we have 

 observcii, is usually of a neat and smooth external texture (figa. 19-'J.'t). 'Dm- 

 tendency of y./>o/^ilrv/>ha to utilize heavy minerals and its selective |iowers 

 appear therefore to us to be conclusively establishetl. for the speciBc gravity 

 of the gems employiHl l>eing much higher than that of quarlx sand, 'J°6*> 

 (gamot. the commonest gem in the aaiid, having a ap. gr. of 3*7 to 4), the gem 

 fragments always sink in the saml at the bottom of the lank. Ivbiw tin- 

 surfoco Uyer, whiob would form Uio norw*l habitn' -' •* - K rtiiunifor." 



*'<hirfnand. Mr AtLftn U Dick, «rb<>luui nuuir ■ ajiocukt •tuiij >>l thr lic-«i ) niinvrmla 

 to Iw (iiuiid in ftlmiMt «ll •And*. h«i> •ug(mlr<l lh>( in inoting ••let (hv lighicr *»iiii M 

 cualiniMlIx Imiiiik ii«*))c<1 •••jr b)r vlutruklKHi, la^Ting th» hc««y ipib«r*l> on lltv turiMw, 

 bal wo rKniv>t accwiit ihu ihpor; in (kc« •■( the comtilii-iui ubtAinini; in <^t laiik>. aiul (•>! 

 ottirr rv**-iui ahich ate aol uut •! Irnijlh in lipn>u Allrn* " Ktalvotcnl i>a tits T)tc<i<7 

 •od l'hon<-raciui u( l'ur|>iMi and Ini< " > ihibtled I7 ihc l*rM»«i«. •« illtwtrKlod by 



HelocUoii utd ILcluktioiu m ihr f : h," Juurn. II. Mxt. Nc , i'.fl.:'. |> Ma 



((uoi-nuU). 



