208 THE AMERICAN MONTHLY [July, 



103. CLATHAROSPYRIS. 



Shell nearly cubical; feet spindle-shaped fusiformis 



104. AEGOSPYRIS. 



Shell tuberculate ; the 4-paired feet twice as long as shell longibarba 



105. ELAPHOSPYRIS. 

 Caudal and sternal feet straight, the 2 pectoral feet S shaped heptaceros 



106. TAUROSPYRIS. 



Feet branched like a deer's antler cervina 



107. THEROSPYRIS 



Surface covered with tubercles; feet club-shaped canis 



108. PETALOSPYRIS. 



Basal plate with 2 pores ; 7-9 conical feet , foveolata 



Basal plate with 3 pores ; 10-12 flat feet .platyacantha 



Basal plate with 4 pores ; 16-20 laminated feet. enpetala 



Basal plate with 4 pores ; 20 25 conical feet tessaromraa 



Ba«al plate with 9 pores ; 20-25 feet argiscus 



Basal plate with 12pores ; 16-20 feet bellidiastrum 



109. ANTHOSPYRIS 



Basal plate with 4 pores ; 9-12 slightly curved feet diaboliscus 



110. CERATOSPYRIS. 



Shell subspherical ; spines not branched. echinus 



Shell nut-shaped ; spines branched. ramosa 



111. GORGOSPYRIS. 



Shell smooth ; 24-30 feet shorter than half the shell ehrenbergii 



Shell tuberculate ; 15-25 feet about as long as the shell lamellosa 



112. CIRCOSPYRIS. 



Shell tuberculate ; horn not toothed at end gigas 



Shellsmooth ; horn with 3 teeth at end tridentata 



113. DICTYOSPYRIS. 



Basal plate with 2 pores ; shell with ramified tubercles stalactites 



Basal plate with 3 semi-circular pores ; shell tuberculate . tristoma 



Basal plate with 3 heart-shaped, 2-lobed pores; shell spinulate. triloba 



Basal plate with 3 pores ; shell smooth gigas 



Basal plate with 4 pores ; shell nearly cubical, smooth fenestra 



Basal plate with 4 pores ; shell nut-shaped, tuberculate tetrastoma 



Basal plate with 4 pores ; shell nut-shaped, spinulate spinulosa 



Basal plate with 6 pores ; shell nut-shaped, tuberculate hexastoma 



