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THE VOYAGE OF THE H.M.S. CHALLENGER.
Synopsis of the Genera of Astrosphærida.
I. Subfamily Coscinommida. (One single latticed shell.) |
Spines all simple, not branched and not tubulous. | All spines of the same kind, | 88. Acanthosphæra. | ||
Larger main spines and smaller by-spines, | 89. Heliosphæra. | ||||
Spines hollow conical tubes with porous walls, | 90. Conosphæra. | ||||
Between simple spines the pores prolonged in hollow tubes, | 91. Coscinomma. | ||||
Spines branched or forked. | Spines with lateral branches, | 92. Cladococcus. | |||
Spines forked or dichotomous, | 93. Elaphococcus. | ||||
II. Subfamily Haliommida.
(Two concentric latticed shells.) |
A. Elatommida, one medullary and one cortical shell. | All spines equal, simple, | 94. Haliomma. | ||
All spines simple, of two different kinds, | 95. Heliosoma. | ||||
Spines branched, | 96. Elatomma. | ||||
B. Diplosphærida, both shells cortical. | No by-spines, | 97. Leptosphæra. | |||
Inner by-spines, | 98. Diplosphæra. | ||||
Outer by-spines, | 99. Drymosphæra. | ||||
Outer and inner by-spines, | 100. Astrosphæra. | ||||
III. Subfamily Actinommida.
(Three concentric latticed shells.) |
Radial spines not branched. | All spines equal, | 101. Actinomma. | ||
Larger main spines and smaller by-spines, | 102. Echinomma. | ||||
Radial spines branched or forked, | 103. Pityomma. | ||||
IV. Subfamily Cromyommida.
(Three concentric latticed shells.) |
Radial spines not branched. | All spines equal, | 104. Cromyomma. | ||
Larger main spines and smaller by-spines, | 105. Cromyechinus. | ||||
Radial spines branched or forked, | 106. Cromyodrymus. | ||||
V. Subfamily Caryommida.
(Numerous, five to ten or more, concentric latticed shells.) |
Two medullary shells and three or more cortical shells (lattice work ordinary), | 107. Caryomma. | |||
No medullary shells (lattice work arachnoidal); three-sided prismatic spines, with verticils of three forked branches. (Arachnosphærida.) | Triangular meshes, simple bars, without diagonal bars, | 108. Arachnopila. | |||
Triangular meshes, simple bars; diagonal bars between the shells, | 109. Arachnopegma. | ||||
Polygonal meshes, bars branched, | 110. Arachnosphæra. |