THE FORAMINIFERA 143 



contour. Fabularia, Def. Similar, but chambers subdivided in the 

 interior. Sigmoilina (Planispirina, pars), Schlumb. (c) Three chambers 

 exposed on the contour of the test. Genus Triloculina, d'Orb. (Figs. 

 22, 6, and 25). (d) Five chambers exposed on the contour of the test. 

 Genus Quinqueloculina, d'Orb. (Fig. 23). (e) In the megalospheric form 

 the second chamber completely invests the megalosphere. Genus 

 Adelosind, d'Orb. Chambers arranged on the quinqueloculine plan, or 

 (in A. polygonia, Schlumb., Fig 26), plano-spirally, three or four to a 

 convolution. (/) Earlier chambers quinqueloculine, later spiroloculine. 

 Genus Massilina, Schl. (</) Miliolinidae trematophorae. Chambers with 

 inner as well as outer walls, and with sieve-like orifices. Eocene and two 

 recent spp. Genera Idalina, M.-Ch. and Schlumb. Test biloculine in 

 later stages, and ultimately uniloculine ; chambers simple (Fig. 27). 

 Periloculina, M.-Ch. and Schlumb. Arrangement similar, but chambers 

 partially subdivided by ridges. Lacazina, M.-Ch. Uniloculine stage 

 assumed early in growth ; chambers subdivided by longitudinal rows of 

 pillars. 



FAMILY 2. HAUERINIDAE. First formed part of test milioline. or 

 Cornuspira-like, later with chambers in spiral or rectilinear arrangement, 

 aperture single. Genera Ophthalmidium, KiibL Piano-spiral, Cornuspira- 

 like at first, later segmented (Fig. 41). Planispirina, Seg. Segmented. 

 Hauerina, d'Orb. Milioline (? quinqueloculine) at first, then piano-spiral. 

 Vertebralina, d'Orb. Piano-spiral at first, then linear. Articulina, d'Orb. 

 Milioline (tri- or quinque-loculine) at first, then linear (Fig. 28). 



FAMILY 3. PENEROPLIDIDAB. Test piano -spiral, crozier- shaped, or 

 cyclical ; usually bilaterally symmetrical ; apertures many. Genera 

 Peneroplis, Montfort. Chambers undivided, arranged plano-spirally 

 throughout, or the later ones rectilinear (Fig. 29). Orbiculina, Lam. 

 Chambers subdivided by secondary septa ; early segments equitant (Figs. 

 30-32). Orbitolites, Lam. Test discoidal, chambers subdivided into 

 chamberlets ; early chambers not equitant ; arrangement at first piano- 

 spiral, then cyclical (Figs. 33-40). Meandropsina, M.-Ch. 



FAMILY 4. ALVEOLINIDAE. Test spiral, elongated in the direction 

 of the axis of convolution. Chambers divided into chamberlets. Genus 

 Alveolina, d'Orb. Test subglobular or fusiform. 



FAMILY 5. KEBAMOSPHAERIDAE. Test spherical, chambers in con- 

 centric layers. Genus K&ramosphaera,. Brady. 



FAMILY 6. NUBECULARIDAE. Test irregular, asymmetrical, usually 

 adherent. Genera Squamulina, Schultze. Test a single adherent 

 chamber. Nubecularia, Def. Test more or less spiral or adherent, often 

 encrusted with sand. 



Calcituba polymorpha, Roboz, appears to be a degenerate form of the 

 Miliolidea. 



ORDER 5. Textularidea. 



Tests of the larger species arenaceous, either with or without a 

 perforated calcareous basis ; smaller forms hyaline and conspicuously 

 perforated. Chambers arranged in two or more alternating series, or 

 spiral, or confused ; often multiform. 



