20 THE AMERICAN MONTHLY [Jan. 



161. THEOPODIUM. 



Shell 3-sided pyramidal, rough, without external strictures pyramidale 



162. PTEROCANIUM. 



Thorax and abdomen with small circular pores, densely crowded 1o- 



gether contiguum 



163. PTEROCODON. 



Shell campanulate, mouth with corona of 12-15 feet campana 



164. PODOCYRTIS. 



Feet cylindrical, as long as the abdomen, little divergent attenuata 



Feet conical, about as long as the thorax, divergent couica 



Feet pyramidal, divergent, as long as the cephalis conulus 



Feet triangular, short, pores 3 times as broad in abdomen as in thorax 



brevipes 

 Feet slightly divergent, short, pores 4-6 times as broad in abdomen as 



in thorax collaris 



Feet nearly parallel, pores 5 times as broad iu abdomen as in thorax 



schomburgkii 

 Feet triangular, stout, divergent, pores 4-6 times as broad in abdomen 



as in thorax veutricosa 



Feet triangular, short, cephalis with cylindrical horn nearly as long as 



the shell euceros 



Feet s-shaped, cephalis with stoat conical horn centriscus 



Feet s-shaped, cephalis with cylindrical horn longer than the shell 



princeps 



Feet short, thick, bent outwards, abdomen urn-shaped urceolata 



Feet conical, slender, divergent, abdomen nearly cylindrical ehrenbergii 



Feet spindle-shaped, slender, divergent, aV)domen inflated argulus 



Feet shovel-shaped, triangular, convergent, length of joints 1-3-1 papalis 



Feet shovel -shaped, semicircular, convergent, length of joints 2-9-4 



mitrella 



Feet shovel-shaped, slightly divergent, length of joints 1-2-3 mitra 



Feet shovel-shaped, triangular, nearly vertical, length ofjoints 1-3-4 



argus 



Feet shovel-shaped, nearly vertical, length of joints 1-2-6 eulophos 



Feet shovel-shaped, convergent, length of joints 1-2-4 sinuosa 



Feet shovel-shaped, convergent, length of joints 2-3-6 floribunda 



Feet shovel-shaped, convergent, very small, length ofjoints 1-4-5 ampla 



Feet shovel-shaped, convergent, very small, length of joints 1-3-3 nana 



Feet shovel-shaped, convergent, short and broad, length ofjoints 2-5-8 



lya;a 



Feet shovel-shaped, nearly vertical, short, length of joints 2-5-5 bromia 



Feet conical, slightly convergent, small, length of joints 1-2-4 tripus 



Feet sub-cylindrical, curved, thin, length ofjoints 1-2-4 tracantha 



165. THYRSOCYRTIS. 



