160 Proceedings of the Roi/al Irish Academy. 



But it nmst be confessed that we have no certain proof that a complex 

 plan of growth implies a higher scale of organization tlian a simple plan, and 

 the fact that some Miliolidae exhibit multiformity in some specimens and 

 not in others shows that it is impossible to disregard trne dimorphism in 

 tlie consideration of multiformity. To mention one classical example only, 

 we should note .Schlumberger's discovery that Biloculina depressa d'Orb. is, 

 in the megalospheric form, biloeuline throughout, while in the microspheric 

 form it passes throngli a quinqueloculine stage, followed by a triloculine, 

 before commencing its normal biloeuline arrangement, and ihnsis, at diHerent 

 stages in the life-history of a single specimen, referable to three different 

 genera. Again, in Aiiiculina conico-artiadata (Batscli) the megalospheric form 

 is adelosine, and tlie microspheric form milioline in its earlier stages, before 

 taking on the rectilinear form of growth." Orhitolitcs tenuusima Carpenter 

 in its earliest stages is identical witli Opthalmidinm, and at a later stage it 

 proceeds on a vert^braiine plan of growth, before adding the concentric 

 orbitoline chambers.'" Remarkable specimens, showing this mulliformity, 

 are among Cai-penter's original type-.specimens in the Exeter Museum. 



Mr. Sidebottom has recently brought to onr notice an interesting example 

 of multiformity exhibited in a series of specimens from a dredging made oti" 

 Darvel Bay (North I'.orneo, Slofnis.). Nvdosaria radictda (Linne) occurs in 

 various forms, typically straight and nodosarine in the variety figured and 

 described by Neugeboren as Nodotaria bet/richi, and curved and dentaline 

 (= Dentalina hreris d'Orbigny). Both of these forms are megalospheric, but 

 microspheric specimens also occur. In these the primordial is followed by a 

 short series of cliambere, arranged on a polymorphine plan, and the shell then 

 completes its growth into a series of dentaline chambers. These microspheric 

 specimens are taxonomic^illy inseparable fronr d'Orbigny's type, iJimorphina 

 nodoxnria, which is usvially regaided as a degenerate Polymorphina, and, taken 

 without consideration of their surroundings, would be placed by syslematists 

 at some distance from Nodosaria radiada (Linn^), whereas an association with 

 a series of specimens from the same dredging proves that they are merely 

 biological mutations -' 



These instances suHice to prove the biological futility of all our systems 

 of taxonomy based on the external shell, and compel us to admit that at 



" We illustr.ite<l and described thi.s multiformity fully inourKerimba Monograph (see 

 notelMn). p. 686, PI. xlv, figs. 2(>-;;;5. 



" De8<-ril>ed and illustrated hy Li.-ter (see note 6), p. 108, el teq., and 6g8. 39,40. 



"These .specimens are figured and descrilted in H. Sidebottom: "Report on the 

 Ilccent ForHmiiiifera Dredged off the Eaat Coast of Australia, etc." J. R. Micr. Soc., 

 1918, p. 162, I'l. iv, tigs. 1-5, and p. 146, Pl.v, figs. 18-22. 



