No attempt is made to classify systematically the taxa in this 

 key. Instead they are listed alphabetically for ease in locating 

 any specific one. 



TTiis key separates, as species, several forms that may not be 

 true biologic species but only phenotypes of a single species, i.e., 

 variant forms that reflect the influence of environment upon the 

 genetic constitution of that species. The two species of Miliam- 

 mina, the two species of Spiroplectammina, and the two species 

 of Buccella may fall into this category of phenotypes. This key 

 separates, as species within different genera, some forms that 

 may belong together as a single species. This feature is especially 

 to be expected in the miliolids, a group that is mutable in a single 

 environment as well as highly variable under different envi- 

 ronments. As an example, Quinqueloculina lata and Thloculina 

 brevidentata could probably be regarded as, respectively, quin- 

 queloculine and triloculine forms of a single species. The solving 

 of such questions is beyond the scope of this key, and it seems 

 convenient to have separate names by which to refer to these 

 distinct forms, whether or not they eventually prove to be 

 distinct species. 



COLLECTION AND STUDY METHODS 



In the intertidal zone, Foraminifera can be collected easily by 

 simple apparatus. Surface sediment can be collected in nested 

 sieves— a 20-mesh screen above and 200-mesh screen below 

 (having openings of 0.850 and 0.0074 mm)— between which the 

 finer sand is caught and concentrated by washing in the ocean 

 water. Sediment clinging to the roots of marsh plants or scraped 

 off slime-coated cobbles can likewise be washed into and con- 

 centrated between the two nested sieves. A plastic syringe, such 

 as an oven baster, can be used to draw up material carefully, 

 with a minimum disturbance of the surface sediment in or on 

 which Foraminifera live. In fine-grained sediments, a plastic 

 core-barrel liner can be forced several inches into the muddy 

 bottom and then withdrawn to remove an undisturbed segment 

 of sediment. In water too deep to use these means, Foraminifera 

 are generally collected by grab samples or corers. More precise 

 details about collecting and culturing have been described by 

 Arnold (1974). 



Foraminifera can be treated by the protein stain Rose Bengal 

 (Walton 1952) in order to determine which of the many 

 specimens in the collection were alive and which were merely 

 empty shells that remained after reproduction or death. 



To prepare a wet sample for study, the sample is washed by a 

 delicate stream of freshwater on a 200-mesh screen, then dried 

 and separated by use of several nested screens into size fractions 

 for ease in examination. Each fraction is spread out thinly on a 

 tray and scanned, using a binocular microscope having 

 magnifications of about x 10- x 90 for the coarser to finer frac- 

 tions. The specimens are picked out from among the sediment 

 grains by use of a moistened sable brush (sizes 000 to 00000 are 

 desirable) and transferred to a cardboard, glass, or plastic shde 

 that has been lightly coated with the water-soluble gum 

 tragacanth. By the use of the moistened brush, an individual 

 specimen can be placed in the most advantageous position for 

 study, or moved into various positions for examination from all 

 aspects. 



BIOLOGY 



The littoral species of Foraminifera are easily maintained alive 

 in small jars or bowls kept under cool and low light conditions. 



and loosely covered to retard evaporation. It is not necessary to 

 add food. The bowl is a self-contained unit in which the 

 Foraminifera live on food materials in the sediment and original 

 seawater in which they were collected. Freshwater should be 

 added occasionally to compensate for evaporation. 



The food of Foraminifera consists of diatoms, filamentous 

 algae, other microscopic algae, and probably also bacteria. 

 Many species contain, within the protoplasm inside the chamber 

 walls, symbiotic algae which provide food for the Foraminifera 

 by photosynthesis. Those species that do not contain symbiotic 

 algae generally feed by ingestion of food outside the test. Some 

 capture their food from the surrounding seawater (filter 

 feeding), others by grazing on the bottom sediment or on slime- 

 covered shells, rocks, plant stems, or other supports that rise 

 above the sea floor (deposit feeding). 



Reproduction in Foraminifera has been studied in only a very 

 few species. Asexual reproduction is accomplished by multiple 

 fission of the parent protoplasm, i.e., the breaking up of the 

 nucleus into many parts so that each embryo receives a part of 

 the parent nucleus. This process leaves the parent test empty. 

 Reproduction normally involves alternation of an asexual and a 

 sexual generation, the two generations having certain dif- 

 ferences in their test morphology. The individuals resulting from 

 the asexual phase generally have a larger initial chamber but a 

 smaller adult size than those resuhing from the sexual phase. 



USE OF THE KEY 



This key is designed as a finding key, not a classification key. 

 It therefore disregards a natural classification and, in a few 

 places, groups together genera that may have little phylogenetic 

 relationship to one another. Moreover, this key applies only to 

 the species of the inshore waters along the northeastern coast of 

 the United States. Because of this restriction, some dichotomous 

 separations are made on combinations of features that elsewhere 

 could not be combined. 



In setting up the key we have tried to use easily recognizable 

 features and to explain, in diagrams and words, the differences 

 between features that are not so easily recognizable. 



The initial dichotomy between agglutinated and secreted tests 

 may become a problem when the agglutination is very fine 



Figures 1,2. — Planispiral coiling. 3. — Trochospiral coiling. 4-6. — I'niserial, 

 biserial, and Iriserial chamber arrangements. 7.— Milioline coiling and quin- 

 queloculine chamber arrangement. 7a. b. opposite sides; 7c, chambers in 

 transverse section. Chamber a is the last formed; chamber b is the next to la.st; 

 chamber c is the third from last, etc. Each chamber as added continues from the 

 aperture of the previous one; thus, the previous aperture, not visible, is at the 

 opposite end of the test. 8.— Milioline coiling and triloculine chamber arrange- 

 ment comparable with that shown in Figure 7. 9. — Sigmoiline chamber 

 arrangement in transverse section. 10. — Biloculine chamber arrangement in 

 transverse section. II.— Coiling of a double row of chambers, i.e., as if a 

 biserial lest (Fig. 5) were bent into a coil. 11a, lateral view; Mb. lateral view 

 opposite to (hat of 11a; lie, edge view. Chambers are identified by numbers (to 

 indicate the sequence of pairs) and letters tto indicate right and left chambers in 

 each pair). 12-14. — Simple tooth, bifid tooth, and valvelike tooth. 15.— Sim- 

 ple terminal aperture. 16. — Terminal aperture at (he end of a neck surrounded 

 by a phialine lip. 17. — Comma-shaped aperture. 18.— Radiate aperture, con- 

 sisting of a terminal aperture surrounded by a ring of radial shts. a. side view; b, 

 top view. 19.— VasiglobuMne aperture, consisting of a terminal aperture sur- 

 rounded by a ring of small pores, a. side view; b, top view. 20.— Two 

 specimens attached by their umbilical surfaces in plaslogamy. 21.— Supple- 

 mentary chambers (s). a whorl of smaller chambers, each covering the inner (um- 

 bilical) part of each larger chamber. 22.— Supplementary pores, an area of 

 large openings over the face of the final chamber. 23. — Septal bridges, a series 

 of prolongations of the chamber extending backward over the depressed suture. 



