REPORT ON THE TETRACTINELLIDA. 
279 
Spicules. — 1. Asters, similar to those of Placina monolopha. 2. Candelabra, dilo- 
phose, the lophose actines directed obliquely towards the outer surface. 
Colour. — White, glistening. 
Habitat. — Trieste. 
Placina trilopha, F. E. Schulze. 
Plakina trilopha, F. E. Schulze, Zeitschr. f. wiss. Zool., Bd. xxxiv. pp. 427, 449, pi. xxi. 
figs. 12-13, 1880. 
Sponge. — Irregular, plate-like, in crusting, no marginal wall. Hypomere forming a 
lacunar network. Ectosome traversed by a network of pore-canals. Hermaphrodite. 
Spicules. — 1. Asters, similar to those of Placina monolopha. 2. Candelabra, trilo- 
phose, or tetralophose ; when trilophose the lophose actines are directed towards the external 
surface, the simple actine vertically inwards, i.e., the spicule is orientated like a trisene. 
Colour. — Y ello wish- white. 
Habitat. — N aples. 
Genus 2. Placortis, F. E. Schulze. 
The ectosome is traversed by a network of widely extending subdermal cavities. 
The canal-system is aphodal, with short, wide aphods. The choanosomal mesoderm is a 
granular collenchyma. The spicules are tri- and diactiiiose ; candelabra are not present. 
Placortis simplex, F. E. Schulze. 
Plalcortis simplex, F. E. Schulze, Zeitschr. f. wiss. Zool., Bd. xxxiv. pp. 430, 449, pi. xxi. 
figs. 14-16, 1880. 
Sponge. — Irregular, smooth, incrusting. 
Spicules. — 1. Asters, triactinose and diactinose, the latter (microxeas) from OT to 
0T5 mm. in length. 
Colour. — Pale yellow. 
Ha bita t. — N aples. 
Family II. C 0 R T i c i d Vosmaer. 
Microsclerophora with tetractinose asters and candelabra. The canal-system is 
aphodal or diplodal. The mesoderm is in part sarcenchymatous, in part chondren- 
chymatous. 
