REPORT ON THE TETRACTINELLIDA. 
clvii 
Family II. Scleeitodermid^. 
Ehabdosa in which the ectosomal spicules are microstrongyles, and the other micro- 
scleres sigmaspires. 
Genus 1. Scleritoderma, 0. Schmidt. 
Sderitoderma, 0. Schmidt, Spong. Meerb. Mexico, p. 28, 1879. 
Scleritodermidse of plate-like form, bearing simple pores on one face and simple 
oscules on the other. 
Type — Scleritoderma 'packardi, 0. Schmidt (p. 346). 
Genus 2. Aciculites, 0. Schmidt. 
Acieulites, 0. Schmidt, Spong. Meerb. Mexico, p. 29, 1879. 
Scleritodermidse in which the ectosomal spicules are rhabdi; microscleres are absent. 
Type — Aciculites higginsii, 0. Schmidt (p. 347). 
Family III. Cladopelti DM . 
Rhabdosa in which the ectosomal spicule is a monocrepid desma highly branched in a 
plane parallel to the surface. Microscleres are absent. 
Genus 1. Siphonidium, 0. Schmidt. 
Leiodermatium, 0. Schmidt, Spong. Atlant. Gebiet., p. 21, 1870. 
„ Zittel, Ahhandl. d. k. baier. Akad. d. Wiss., Bd. i. p. 103, 1878. 
Siphonidium, 0. Schmidt, Spong. Meerb. Mexico, p. 28, 1878. 
Leiodermatium, Vosmaer, Bronn’s Klass. u. Ord. d. Thierreichs, Porifera, p. 290, 1886. 
The oscules are borne at the ends of narrow tubular prolongations extending outwards 
from the sponge body. 
Type — Siphonidium ramosum, 0. Schmidt (p. 348). 
Suborder II. ANOPLIA. 
Lithistida in which special ectosomal spicules and microscleres are absent. 
