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THE VOYAGE OF H.M.S. CHALLENGER. 
Suborder II. MENISCOPHORA. 
Monaxonida in which the microsclere when present is usually a sigmaspire, sigma, 
or chela, never an aster. 
Family I, Heteroraphid^, Ridley and Dendy. 
HeterorrTiapMdB, Ridley and Dendy, loc. cit. 
Family II. Desmacidonida:(0. Schmidt), Ridley and Dendy {emend.). 
Desmacidonidx, Ridley and Dendy, loc. cit. 
Suborder III. SPINTHAROPHORA. 
Monaxonida in which the microsclere when present is some form of aster, never a 
sigmaspire, sigma, or chela. 
Group I. Homosclera. 
Spintharophora in which the spicules are of the same or a similar order, i.e., all 
microscleres. 
Family I. Astropeplid^. 
Homosclera in which the microscleres are microxeas and asters. The microxeas 
are arranged tangentially to the walls of the canal-system, forming a loose felt. The 
chamber-system is eurypylous, the ectosome is not a cortex. 
Genus 1. Astropeplus, n. gen., with a single species, Astropeplus pulcher, n. sp. 
Group II. Heterosclera. 
Spintharophora in which megascleres are always present and sometimes also 
microscleres. 
Demus I. Centrospinthara. 
Heterosclera in which the microsclere when present is a euaster. 
