264 The Sarcodina 



of perforations distinguishes a few families with calcareous tests from the 

 majority which have perforate tests. Families with arenaceous tests are 

 differentiated by the number of chambers — one, two, or many — and by 

 the patterns in which the chambers are arranged in the multilocular 

 types. The form of the test (Fig. 5. 37) and the type of aperture (Fig. 5. 





Fig. 5. 44. Allogromiidae: A. Amphitrema wrightianum Archer, schematic, 

 x375 (after Cash). B. Diplophrys archeri Barker (diameter of test, 8-20/i), 

 schematic optical section showing nucleus and large refractile inclusion; test 

 thin, hyaline (after Penard). C, D. Artodiscus saltans Penard (body, \8-2Sii); 

 entire organism showing pseudopodia unlike those of typical Foraminiferida 

 (C); single pseudopodium emerging through test (D); schematic (after P.). 

 E. Allogromia (Gromia) dujardini Schulze, x29 (after S.) F. Lecythium 

 granulatum (Schulze) Hopkinson, x360 (after S.). G. Amphitrema stenostoma 

 Nusslin, schematic optical section (after Penard). 



38) also are bases for differentiating genera and species. In the most 

 primitive family, the Allogromiidae, a chitinous test is characteristic of 

 the adult organism. 



Family Allogromiidae. The test is completely or mostly chitinous, usu- 

 ally with a single aperture, sometimes with an opening at each end. The 

 wall may be a single chitinous layer, thin in some forms and relatively 



