REVISION OF FRESHWATER SPONGES OF SPONGILLIDAE 147 



Color in life. — Not yet observed; dry sponge recorded as light 

 lead-brown. 



Discussion. — This species seems to differ from U. corallioides only 

 by its possession of gemmules and by its branchless encrusting growth. 

 Future studies may yet establish its identity ^^^th the former, but the 

 present material does not permit any rehable conclusions in this 

 regard. 



Genus Metania Gray, 1867, redefined 



Metania Gray, 1867, p. 551. — De Laubenfels, 1936, p. 36. — Burton, 1938, p. 463 

 (part synonymy only). — Jewell, 1952, p. 450. — Penney, 1960, p. 45. 



Tubella Carter, 1881a, p. 96 (part) .—Potts, 1887, p. 248 (part) .— Annandale, 

 1909f, p. 102; 1911c, p. 120; 1918a, p. 213.— Gee, 1933c, p. 237 (part). 



Acalle Burton, 1934, p. 412 (non Gray, 1867, p. 552). 



(Not Tubella Lendenfeld, 1887, p. 90) 



Type species. — SpongiUa reticulata Bowerbank (1863). 



Definition. — ]\Iegascleres stout amphistrongyla or amphioxea, 

 smooth or microspined, often differing in length in the same individual, 

 occasionally of two distinct classes. 



Microscleres present in all species, but of varying abundance; 

 they are slender, fusiform, and spined amphioxea, with their central 

 spines large and erect. 



Gemmoscleres tubelliform, with more or less spiny shafts; lower 

 rotule circular or irregularly polygonal, with or without marginal 

 indentations, often with radial striations; upper rotule invariably 

 knoblike, either represented by a rounded boss, or bearing a number 

 of recurved marginal spines. 



Gemmules abundant in matm*e sponge, large and spherical, usually 

 scattered through skeletal meshes, rarely restricted to base; pneu- 

 matic layer feebly developed, often thin, consisting of rather large 

 polygonal air spaces; gemmoscleres embedded in this strictly radially, 

 resting with fidly developed rotule on inner gemmular membrane, and 

 projecting with terminal knob beyond surface of pneumatic coat; 

 outer gemmular membrane iU-defined or absent; foramen tubular, 

 porus tube straight and comparatively short, surrounded by a circle 

 of slanting gemmoscleres. 



Sponges invariably bulbous and massive, in growth often resembling 

 the structure of a wasp nest, surface rather reticulate and hispid; 

 color in life dark gray to dark brown; consistency rigid but quite 

 brittle. 



Apparently restricted to the tropics, possessing a discontinuous 

 distribution; not yet found in tropical Australia. 



Discussion. — The genus Metania Gray, as here redefined, includes 

 all those species with true tubelliform gemmoscleres which possess 



279^30—68 12 



