Sollas — On TetracUnellid Sponges. 195 



Psammastra murrayi, sp. n. — Sponge spherical, with two or 

 three oscules ; surface raised generally into conuli, and produced 

 here and there into strong fibrous bands for attachment; cortex 

 thick, containing imbedded grains of sand. Spicules — (lj acerate, 

 4-65, and over,°by 0*065 mm. ; (2) fork, 3*9 by 0-071 mm. ; arms 

 simple, regularly curved outward and forward, 0-097 to 0*116 mm. 

 long ; spread, 0-161 to 0-175 mm. ; (3) modified fork ; a conical 

 spicule, with rounded distal base, and three short spines given off 

 near the distal end ; the axial ray of the spines descends outwards 

 and downwards through the spicular shaft, but bends into hori- 

 zontal position as it enters the rays or spines, which may be simple 

 or bifurcate, the bifurcation taking place in a horizontal or vertical 

 plane ; (4) stellates, a variety with large centrum and short rays, 

 0-012 to 0.016 mm. in diameter, passing into a second variety 

 with small centrum and longer rays, 0-016 to 0-024 mm. in dia- 

 meter ; (5) bacillus, a cylindrical rod with rounded ends, micro- 

 spined irregularly over the whole surface ; sometimes constricted 

 in the middle, 0*018 to 0-016 by 0-004 mm. Colour, russet brown 

 on upper surface where exposed to the light ; pale grey below. 



Habitat.— Station 162, lat. 39° 10' 30" S. ; long. 146° 37' E. 

 38 fms. 



Family. GEODINID^. 



Genus 1. Erylus, Gray. Genus 4. Synops, Vosmaer. 



„ 2. Caminus, Schmidt. „ 5. Isops, Sollas. 



„ 3. Cydonium, Miiller. „ 6. Geodia, Lamk. 



Of the genus Geodia no examples occur in the Challenger 

 Collection. 



Synops is an exceedingly natural genus, characterized, not only 

 by the restriction of the oscules to one surface, but also by the 

 general characters of its spicules ; anchors rarely occur, and the 

 arms of the forks are usually simple. 



Description of Species. 



Erylus formosus, sp. n. — Sponge massive, growing into ridges 

 and lobes, attached ; oscules round, few ; pores large, each the 

 simple opening of an incurrent chone. Spicules — (1) acerate, 

 0-9 by 0-024 mm. ; (2) fork, shaft, 0-4 by 0-024 mm. ; arms simple ; 



P3 



