clvi 
THE VOYAGE OE H.M.S. CHALLENGER. 
Family III. Pleromida:. 
Megamorina, Zittel, Abhandl. d. k. baier. Akad. d. Wiss., Bd. i. p. 99, 1878. 
Megamorinidse, Vosmaer, Bronn’s Klass. u. Ord. d. Tbierreichs, Porifera, p. 295, 1886. 
■ „ {pars), Sollas, Encyclopaedia Britannica, vol. xxii. p. 424, 1887. 
Trisenosa in which the desma is monocrepid and smooth, not tuberculated ; zygosis 
occurs between the ends of the cladi of one desma and the epirabd of another. Chamber- 
system aphodal. 
Genus 1. Fleroma, n. gen. 
Pleromidae in which the flagellated chambers are large, with wide short aphodi. The 
microscleres are microxeas and spirasters. 
Typ e — Pleroma turhinatum, n. sp. (p. 312). 
Genus 2. Lyidium, 0. Schmidt. 
Lyidium, O. Schmidt, Spong. Atlant. Gebiet., p. 84, 1870. 
„ Zittel, Abhandl. d. k. baier. Akad. d. Wiss., Bd. i. pp. 99, 132, 1878. 
“ Sponge dish-shaped, on both sides simple canals open by large round ostia. [Desma] 
smooth, crooked, branched, the branches terminating in a disciform, or cup-shaped 
expansion. In the sarcode of the surface numerous simple [strongyles] of eonsiderable 
size oecur.” — (Zittel). 
Type — Lyidium torquilla, 0. Schmidt (p. 343). 
Demus II. Ehabdosa. 
Hoplophora in which the ectosomal spicules are microstrongyles, or modified 
microstrongyles (discs). The desmas are monocrepid. 
Family I. Neopeltida:. 
Ehabdosa in which the eetosomal spicules are monoerepid discs. 
Genus 1. Neopelta, 0. Schmidt. 
Neopelta, O. Schmidt, Spong. Meerb. Mexico, p. 88, 1880. 
Neopeltidse in which the microscleres are microrabds and spirasters. 
Type — Neopelta perfecta, 0. Schmidt (p. 344). 
