XXVill THE VOYAGE OF H.M.S. CHALLENGER. 
details in an outline sketch of our attempt to put together the scattered evidences and to 
trace the lost records of the pedigree of life. 
The following is a summary of the classification I have adopted :— 
Crass ASTEROIDEA. 
Sub-class HUASTEROIDEA, Sladen, 1886.1 
Order I. PHANEROZONIA, Sladen, 1886. 
[SrenopNeusiIA : EurysrRorerta. | 
Euasteroidea with marginal plates large and highly developed in the adult. The 
supero-marginal and the infero-marginal plates contingent and with their axes usually in 
parallel planes. Papulz restricted to the abactinal area, circumscribed by the supero- 
marginal plates. Ambulacral plates well spaced and usually broad, the development of 
the ambulacral skeleton being retarded, or concurrent with that of the test generally. 
Actinostomial ring with the adambulacral plates prominent. Pedicellarie valvate, fora- 
minate, or excavate. 
Family I. ARcHASTERID# (Viguier, 1878), emend. Sladen, 1886. 
Phanerozonate Asterids with thick and massive marginal plates bearing spines or spini- 
form papille. Abactinal skeleton with simple spiniform spicules, with pseudo-paxille, 
or with true paxillz. Actinal interradial areas with plates bearing spinelets. Adam- 
bulacral plates large and not compressed. Proctuchous. Pedicellarize frequently present. 
No superambulacral plates. 
Subfamily 1. PARARCHASTERINA, Sladen, 1886. 
Archasteride with the papule confined to a limited area at the base of the ray. 
Marginal plates more or less alternate. Actinal intermediate plates absent or very few in 
number. 
Genus 1. Pararchaster, Sladen. 
Genus 2. Pontaster, Sladen. 
Subfamily 2. PLuronasTeRINa, Sladen, 1886. 
Archasteridze with the papule distributed over the whole abactinal area. Marginal 
plates opposite. Actinal intermediate plates well developed. No definite medio-radial 
line of abactinal plates. ; 
Genus 1. Dytaster, Sladen. 
Genus 2. Plutonaster, Sladen. 
Genus 3. Lonchotaster, Sladen. 
1 Date when the corresponding sheet of the descriptive portion of this work left my hands for press. 
