REPORT ON THE TETRACTINELLIDA. 
cxli 
Genus 14. Papyrula, 0. Schmidt. 
Papyrula, 0. Schmidt, Spong. Kiiste v. Algiers, p. 18, 1868. 
The microscleres are a euaster and a microrahd. The ectosome is thin and densely 
crowded with microxeas. 
Type — Papyrula candidata, 0. Schmidt (p. 199). 
Genus 15. Psammastra, SoUas. 
Psammastra, Sollas, Sci. Proc. Roy. Dubl. Soc., vol. v. p. 194, 1886. 
Cortex thick, fibrous, containing embedded foreign bodies ; surface conulose. The 
megascleres include modified plagiotrisenes. In addition to euasters a microrabd is present. 
Type — Psammastra mur ray i, Sollas (p. 175). 
Genus 16. Algol, n. gen. 
The ectosome is thin, not fibrous, and contains tangentially scattered oxeas. The 
microscleres are a chiaster and a comparatively large microrabd. The megascleres are 
partly radially and partly irregularly arranged. 
Type — Algol corticata (Carter) (p. 200). 
Phylogeny of the Stellettida:. 
Diayringa 
Tethyopsis 
Draymastra 
Trihraeliium Astrella 
I ! 
Stryphnus Ancorina Pilochrota 
Psammastra? 
Ecionema Myriastra- 
Psammastra ? Stelletta 
Papyrula 
Algol Aurora 
Stryphnus? 
Anthastra 
Appendix to the Euastrosa. 
Family Epipolasida:. 
Euastrosa (?) without trisenes^ possessing oxeas and one or more forms of aster. The 
oxeas arranged partly in radiating fibres, partly scattered loosely in the choanosome ; in 
the ectosome disposed tangentially. The chamber-system (so far as investigated) aphodal. 
