258 REPORT OF NATIONAL MUSEUM, 1897. 



ANALYTICAL KEY TO FAMILIES. 



Subkingdom Protozoa. — Body consisting of a minute mass of protoplasm, or an 



aggregation of such masses, without differentiation of parts into organs or tissues, 

 either with or- without a testaceous euvelope or skeletal framework. 



Class RiiizoroDA. — Protoplasmic body capable of protruding any portion of its 

 substance in tbe shape of lobes, bands, or threads, for the purpose of locomotion or 

 the prehension of food; generally more or less completely inclosed in a testaceous 

 envelope; nucleus and contractile vesicle present or absent. 



Order Foraminifera. — Pseudopodia protruded as fine threads which (low together 

 wherever they touch, forming a network of granular protoplasm; nucleus and 

 vacuoles generally indistinguishable; tests either chitinous, calcareous, or of agglu- 

 tinated sand or shells, never silicious. 

 Test chitinous, sometimes encrusted with foreign bodies. 



Aperture at one or both extremities. Family I. Gromid^e. 



Test arenaceous (composed of mud, sand, shells, or sponge spicules). 



Relatively large, one-chambered, or sometimes uusymmetrically segmented by 



constriction or adhesion, never truly septate Family II. Astrorhizii>k. 



Relatively small, usually regular in contour, one or many chambered; many- 

 chambered forms sometimes imperfectly septate, often labyrinthic : 



Family III. Lituolid i;. 

 Test arenaceous or calcareous. 



Segments in two or more alternating series, or spiral or confused, often dimor- 

 phous Family IV. Textularid.k. 



Test calcareous. 



Imperforate, porcellanous Family V. Miliolid.k. 



Perforate, hyaline. 



Chambers one, or many joined in a straight, curved, spiral, alternating, 

 or branching series; aperture simple or radiate, terminal: 



Family VI. Lagenid^e. 

 Chambers more or less embracing, following each other from the same end, 

 or alternately at either end, or in cycles of three : 



Family VII. Chilostomellii> k. 

 Chambers comparatively few, inflated, spirally arranged; apertures single 



or multiple, conspicuous Family VIII. Globigerinid k. 



Chambers typically spiral and rotaliform — all the segments visible on the 

 upper side, those of the last convolution only on the lower (apertural) 

 side. Aberrant forms evolute, outspread, acervuline, or irregular: 



Family IX. Potalid.e. 



Chambers spiral or concentric; shell symmetrical, usually lenticular or dis- 



coidal Family X. Numml t linii>.e. 



analytical key to genera. 



Family I. Gromid.i;. 

 Aperture single. 



Test large, ovate. 



Mouth central, in a depression at the broad end; test closely adherent to 



the body of the animal Genus Lieberkuhnia. 'i- 



Mouth terminal; test not adherent Genus Gr-omia. 



Test minute, ovate. 



Mouth prominent, one-sided Genus Mikrogromia. 



Test composed largely of foreign bodies (diatoms, etc.).. .Genus Diaphoropodon. 



Aperture at each end. * 



Test hyaline, tubular, cylindrical, or flattened Genus Shepheardella. 



