208 



THE VOYAGE OF H.M.S. CHALLENGER. 



L Subfamily 



Coscinommida. 

 (One single latticed shell. ) 



IL Subfamily 



Haliommida. 

 (Two concentric latticed 

 shells. ) 



III. Subfamily 



Actinommida. 

 (Three concentric latticed 

 shells. ) 



R^ Subfamily 



Cromyommida. 

 (Four concenti-ic latticed 

 shells. ) 



Synopsis of the Genera of Astrosphwrida. 



f All spines of the same 

 Spines all simple, not | kind, .... 

 branched and not tubu- J. 



lous. I Larger main spines and 



[ smaller by-spines, 



Spines liollow conical tubes with porous walls. 



Between simple spines the pores prolonged in hollow 

 tubes, ......... 



f Spines with lateral 

 branches. 



Spines branched or forked. -{ 



Spines forked or dichoto- 

 [ mous, 



f All spines equal, simple. 



A. Elatommida, one medul- 

 lary and one cortical -j 

 .shell. I 



B. Diplosphaerida, both 

 shells cortical. 



Radial spines not branched. 



All spines simple, of two 

 different kinds, 



Spines branched. 



No by-sjiines, . 



Inner by-spines, 



Outer by-spines, 



Outer and inner by -spines, 



All spines equal. 



Larger main spines and 

 smaller by-spines. 



Radial spines branched or forked. 



All spines equal, 



Radial spines not branched. 



Larger main spines and 

 smaller by-spines. 



V. Subfamily 



Caryommida. 

 (Numerous, five to ten or 

 more, concentric latticed 

 shells. ) 



Radial spines branched or forked, .... 



Two medullary shells and three or more cortical shells 

 (lattice work ordinary), ...... 



No medullary shells (lattice 

 work arachnoidal); three- 

 sided prismatic spines, - 

 with verticils of three 

 forked branches. 



( Arachnosphserida. ) 



Triangular meshes, simple 

 bars, without diagonal 

 bars, .... 



Triangular meshes, simple 

 bars ; diagonal bars 

 between the shells. 



Polygonal meshes, bars 

 branched, . 



88. Acanthospkcera. 



89. Heliosphmra. 



90. Conosphcera. 



91. Coschwmma. 



92. Cladococcus. 



93. Elaphococciis. 



94. Haliomma. 



95. Hdiosoma. 



96. Elatomma. 



97. Leptosphcera. 



98. Diplosphmra. 

 9 9 . Drymospluera. 



100. Astrosphcera. 



101. Actinomma. 



102. EcMnomma. ' 



103. Pityomiiia. 



104. Cromyomma. 



10.5. Cromy echinus. 



106. Cromyodrymus. 



107. Caryomma. 



108. AraeJmopila. 



109. Arachnopegma. 



110. Arac/mosphcera. 



