176 Proceedings of the Royal Irish Academy. 



Auother surprise awaited us when we came to examine the material from 

 the tank which had been filled with superlimed (hypertonic) sea-wat«r. A 

 considerable proportion of the specimens of Vcrnatilina pohjstroplia were 

 monsters. They include specimens witli supernumei-ary or abortive ch'ambers, 

 in some cases almost fistulose. Other specimens born in our tank were 

 actual monstrosities. There were complete pairs of tests joined together 

 mouth to apex (fig. 24\ and other specimens joined apex to apex (figs. 25-27), 

 and yet others presenting every conceivable eccentricity of foini and 

 development (figs. 28-33). The influence of artificially enriched wat«r upon 

 the life-habits of the Foraminifera appears therefore to us to be established 

 in the case of V. pohjstropha in the same way as it was in the earlier 

 esperiment with MassUina secans. 



As a check experiment, we placed in the same superlimed water a 

 quantity of living Massilina secans. When examined it was found that tests 

 presumably adult when placed in the tank had added later monstrous 

 chambers, whilst others born in the tank were wholly monstrous ah initio, 

 the chambers running riot, as it were (figs. 36-43) ; and again we found, 

 sometimes combined in a single test, the characteristic features of the three 

 species produced in the earlier experiment. Other specimens had proceeded, 

 after the completion of the milioline shell, to add rectilinear chambers in the 

 manner of Vertebralina or Articulina(fig. 44). In one instance a perfectly 

 chitiaous shell had added a terminal chamber perfectly and normally 

 calcareous (fig. 45). 



Whilst this paper has been in course of preparation, we have received 

 fronj Mr. Henry Sidebottom a small sample of material dredged in eight 

 fathoms from " White Dog's Anchorage, River Min, China," containing a 

 remarkable series of tests of Tertulnria lucidtmta, Brady, some of wliich 

 exhibit the same striking feature of projecting mineial fragments as our new 

 Selsey variety of V. pdyistropha (figs. 46-48). The occurrence is of greal 

 interest, because the Textularians are as a rule very neat builders. Indeed 

 outside the Astrorhizidae the inxariable habit of species constructing 

 adventitious tests is to incorporate the material employed as evenly as 

 possible. We have no information as to the nature of the dredging, but it 

 seems possible that the Eiver Win Textularians suffered from the same lack 

 of fine material as the Verneuilinae in our Selsey tank, and so were forced 

 to employ mineral fragments of abnormal size. 



To sum up the results of the observations which are recorded in this paper, 

 it seems clear that if the biological characters which determine species are 

 originated and evolved, as appears to be the case in the Metazoa, by the 

 circumstances of environment, the argument holds good with enormously 



