122 PROTOZOA. 



considered to be natural. It is now well known that many of the 

 Arenaceous Foraminifera^ forming one of the principal groups in the 

 old section of the Imperforate have diffused pseudopodial apertures, 

 with or without a general aperture as well, so that their test is truly 

 " perforate." The retention of the sections Perforata and Imperfo- 

 rate!, would therefore necessitate the splitting up of the Arenaceous 

 Foraminifera into two series, one with a " perforate " and the other 

 with an "imperforate" test. In view of this fact, Dr Brady has 

 abandoned the minute structure of the test as an exclusive basis for 

 the classification of the Fora??iinifera, and has proposed the follow- 

 ing arrangement of the order into families : — 



Order Foraminifera (Reticularia). 



Family i. Gromid^e. — Test chitinous ; smooth or encrusted with 

 foreign bodies ; with a pseudopodial aperture at one or both extremities. 

 Ex. — Gromia, Microgromia, Lieberkiihnia. 



Family 2. Miliolid^e. — Test imperforate ; normally calcareous and 

 porcellanous, sometimes encrusted with sand, or, under certain condi- 

 tions, chitinous or siliceous. Ex. — Biloailina, Peneroplis, Orbitolites. 



Family 3. AstrorhizidtE. — Test composed of sand-grains or other 

 foreign bodies, usually more or less united into a coherent test by a 

 cementing material. Usually the test is monothalamous, often branched 

 or radiate, sometimes partially subdivided, but seldom or never truly 

 septate. Ex. — Astrorhiza (fig. 19, A), Rhabdammina, Saceammina. 



Family 4. LiTUOLiDiE. — Test arenaceous, usually regular in contour ; 

 septation of the polythalamous forms often imperfect ; chambers fre- 

 quently labyrinthic. Ex. — Litiwla, Trochammina (fig. 19, B and C), 

 Endothyra. 



Family 5. Textularid^e. — Tests of the larger species arenaceous, 

 with or without a perforate calcareous basis ; smaller forms hyaline and 

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

 spiral, or confused. Ex. — Textnlaria, Valvulina. 



Family 6. Chilostomellid^e. — Test calcareous, perforate, polythala- 

 mous. Segments following each other from the same end of the long 

 axis, or alternately at the two ends, or in cycles of three ; more or less 

 embracing. Aperture a curved slit at the end or margin of the final 

 segment. Ex. — Chilostomella. 



Family 7. Lagenid^e. — Test calcareous, finely perforated ; either 

 monothalamous, or consisting of a number of chambers joined in a 

 straight, curved, spiral, alternating, or (rarely) branched series. Aperture 

 simple or radiate, terminal. No interseptal skeleton nor canal-system. 

 Ex. — Lagena, Nodosaria, Cristellaria. 



Family 8. Globigerinidte. — Test free, calcareous, perforate ; cham- 

 bers few, inflated, arranged spirally. Aperture single or multiple, con- 

 spicuous. No supplementary skeleton nor canal-system. Ex. — Globi- 

 gerina, Orbidina. 



Family 9. Rotalid^e. — Test calcareous, perforate ; free or adherent. 

 Typically spiral and " rotaliform" — i.e., coiled in such a manner that the 

 whole of the segments are visible on the upper surface, those of the last 

 convolution only on the inferior or apertural side, sometimes one face 

 being more convex, sometimes the other. Aberrant forms evolute, out- 

 spread, acervuline or irregular. Some of the higher modifications with 





