CLASSIFICATION. 
S pong. 11 
Subord. 1. Lyssacina, Zittel. Hexactinellida , in which the 
spicules always remain isolated, or subsequently are 
partly united by silica in an irregular manner. 
Tribe 1. Hexasleropliora , F. E. S. Hexasters constantly occur 
in the parenchyma. The chambers are sharply sepa- 
rated from each other : thimble-shaped. 
Fam. 1. Euplectellidce. Thin walled sac tubes or sacs, with 
dagger-shaped hexacte hyperdomalia, having a 
long proximal ray. 
Subfam. 1. Euplectellinai. Tubular, with terminal trans- 
verse sieve-plate. In the lateral wall circular 
gaps, more or less regularly arranged. On 
the projecting distal ray of the dagger-shaped 
hexacte-hypodermalia a floricome is situated. 
Genus 1. Euplectella , Owen (p. 37). 
Species i, E. aspergillum, Owen; ii, E. suberea^Ny.Th . ; 
iii, E. cucumer , Owen ; iv, E. jovis , 0. Sdt. ; 
v, E. owcni, Marshl. ; vi, E. crassistellata, 
F. E. S. ; vii, E. nodosa , F. E. S. 
Genus 2. Regadrella , 0. Sdt. A tube attached by a 
knotty bas il part; discohexasters in the paren- 
chyma (p. 39). 
Species i, R. phoenix , 0. Sdt. 
Subfam. 2. Holascmce , F. E. S. Tubular ; without gaps in 
the wall ; without superficially situated flori- 
comes. 
Genus 1. Ilolascus , n. g., F. E. S. (p. 39). 
Species i, H. stellaius , n. sp. ; ii, II. fihulatus , n. sp. ; 
iii, II. polejaevi, n. sp. ; iv, II. ridleyi , n. sp. 
Genus 2. Malacosaccus , n. g. (p. 41). 
Species i, M. vastus , n. sp. ; ii, M. unguiculatus, n. sp. 
Subfam. 3. Tangerines, F. E. S. The wall of the sac or 
tube-shaped body is perforated by gaps of 
different dimensions, irregularly shaped and 
distributed. Reticulate trabeculae of the 
skeleton of the wall form an irregular frame- 
work of principalia partly cemented together. 
On each distal ray of the dagger-shaped hypo- 
dermal hexactes is seated a floricome. 
Genus 1. Tcegeria t n. g. (p. 41). 
Species, T.pulchi'a f n. sp. 
Genus 2. Walteria, n. g. (p. 42). 
Species, W. flemmingii , n. sp. 
Genera, the exact position of which is uncertain, but 
allied to the Euplectellidce. 
Genus 1. Hahrodictyon , Wy. Th., p. 42. 
Species i, H. speciosum , O & G. 
Genus 2. Eudictyon, Marshall, p. 43. 
Species i, E. elegans f Marshl. 
1886. [vol. xxiii.] f 4 
