DESCRIPTIVE CATALOGUE OF RECENT FORAMINIFERA. 201 



Test typically bi- or tri-serial, etc. — Continued. 

 Monomorphous — Continued. 



Segments alternatinji in three rows. 



Aperture as in Te.rlidaria Genus rerneniUna. 



Aperture simple, produced, central (Jenus Trilaxia. 



Aperture porous Genus ChrysalUUna. 



Seijnieuts arranged S])irally, with three chambers in each convolution. 



Aperture jiartially covered by a valvuh^r lip Genus !'iilruli»a. 



Dimorphous. 



Early chambers biserial, later ones uniserial and rectilinear: 



(Jenus Jliffciicrhia. 

 Early chambers small and biserial, later ones broadly arched and uniserial: 



Genus Pavonina. 



Early chambers planosi^iral, later ones biserial Genus Spiroplecta. 



Early chambers triscrial. later ones uniserial and rectilinear: 



Genus Chimliua. 



Early chambers triserial, later ones biserial Genus (iaittirijina. 



Test typically spiral; sometimes bi- or tri-serial; aperture oblique, comma-shaped 



or some modification of that form jt Subfamily IUi.iminin.e. 



Monomorphous. 



Spiral, elongate, more or less tapering, often triserial Genus Bulimhia. 



Much elongated, with a tendency to become asymmetrically biserial: 



Genus Virfiitl'nia. 



Distinctly biserial, Textularian Genus Iloliriva. 



liiserial; aperture an arched or semicircular orifice with a vertical notch on 



the septal face of the last segment Genus I'lenroatomvlla. 



Dimorphous. 



Early segments bulimine or virguline, later ones uniserial.. Genus Bifariua. 

 Test consisting of a double series of alternating segments, more or less coih>(l upon 



itself Subfamily Cas.sidulixin.e. 



roUled on its long axis, and coiled more or less completely upon itself: 



Genus Cassidnlina. 

 IJroad, arched on the dorsal side, slightlj' coiled Genus Ehrenberyia. 



Family V. Mii.ioMD.E. 



Test irregular, asymmetrical: aperture variable Subfamily Nubeci'Laiun.e. 



Cliaml)er one, inflated, adherent; ajx-rtureon the convex surface: 



(ienns Sr/uamulina. 

 Chambers more than one, in linear or very irregularly spiral series: 



Genus 2\'ubecn1aria. 

 Test coiled on an elongated axis, in a single plane or inequiliiterally ; chambers two 



in each convolution Subfamily Miuolimn.e. 



Chambers in a single plane, embracing, the last two only visible: 



(Jenus JUlociiUna. 



Ciiambers biloculine but subdivided in the interior Genus Fahularin. 



Chambers in a single plane, all visible on both sides of the shell: 



Genus SpiroIocuUna. 

 Cltambers inequilateral, coiled round the long axis of the shell so that more than 



two (usually three or five) are visible Genus Miliolina. 



Test <limorpliou8; partly milioline, partly spiral or rectilinear: 



Subfamily Haikiunin.e. 



Early chambers milioline, subsequently in a straight series (ienus Articidina. 



Early chambers partly milioline and ]>aitly planospiral. subseciuently in a straight 



series (Jenus J'erlehralina. 



Early chamber an undivided planospiral tube, subse(]ucntly with two or more 

 segments in each convolution (ienus Ophllinlmidinm. 



