22 THE AMERICAN MONTHLY [Jan. 



Abdomen truncate, conical, with 16-34 divergent ribs spatiosa 



Abdomen cylindrical, with 12 parallel ribs stiligera 



174. CA.LOCYLAS. 



Peristome with 15-20 feet about as long as the abdomen turris 



Peristome with 12 15 feet half as long as the abdomen erinaceus 



Peristome with 20-30 feet about half as long as the cephalis gigas 



175. CLATHROCYCLAS. 



Peristome with 12-15 slender curved feet fimbriata 



Peristome with 15-20 triangular feet puella 



Peristome with 9-12 triangular feet, domina 



176. THEOCALYPTRA. 



Length of joints 1-2-2, abdomen with 3 circles of large pores discoides 



177. THEOCONUS. 

 Shell thorny, cephalis with horn I2-2 times as long as the shell... long icorni 



Shell thorny, cephalis with horn of same length ampullaceus 



Shell conical, smooth, cephalis with horn as long as the thorax amplus 



Shell smooth, cephalis with denticulate horn 2-3 times the length 



dionysius 

 Shell pear-shaped, smooth, cephalis very small with horn 3 times the 



length fiscus 



178. LOPHOCONUS. 



Cephalis with 8-12 divergent, conical horns apiculatus 



179. THEOCYRTIS. 



Pores quincuncially disposed, about as broad as the bars, shell smooth 



barbadensis 



Pores quincuncially disposed, twice as broad as the bars. cylindrica 



Pores in transverse rows, 3 in thorax, 6 8 in abdomen elegans 



Pores in transverse rows, 1-2 in thorax, 3-5 in abdomen paupera 



Pores quincuncially disposed, shell a little rough microtheca 



Pores in transverse rows, 5-6 in thorax, 8-10 in abdomen macroceros 



Pores quincuncially disposed in the thorax, shell thorny ..aspera 



Pores quincuncially disposed in thorax, abdomen with coronal of 9 



large pores and 2-4 transverse rows of smaller pores cenophila 



180. THEOSYRINGIUM. 

 Abdomen prolonged into a slender, cylindrical tube tubulus 



181. LOPHOCYRTIS. 



Shell with one deep stricture, cephalis with 3-9 spines stephanophora 



Shell with two deep strictures, cephalis with 4-8 spines coronata 



Shell with two distinct strictures, cephalis with 2 curved horns biaurita 



182. TRICOLOCAMPE. 



Pores sub-regular, regularly disposed in transverse rows poly zona 



Pores irregular, irregularly disposed panthera 



