REPORT ON THE TETRACTINELLIDA. 
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Genus 2. Tretolophus, n. gen. 
Azoricidse in whicli the oscules are arranged in a linear series along the summit of a 
ridge-like elevation. Main excurrent canals more or less vertical. 
This genus is provisional, founded on a single dead specimen. 
Tretolophus paniceus, n. sp. 
Sponge. — Small, attached by an irregular base, ridge-like. Oscules small, 0*7 to 
0'8 mm. in diameter, arranged in a series on the summit of the ridge, the simple openings 
of vertically descending excurrent canals. 
Spicules . — I. Megascleres. 1. Desmas, like those of Azorica; epirabd and cladi short 
and thick, bearing numerous stout tubercles which terminate in long, simple or bifid 
spines, diameter of the epirabd about 0'03 to 0'04 mm., sometimes more ; crepidial axis 
0’02 mm. in length. 
2. Strongyloxea {?), 0'2 by 0'002 mm. 
II. Microscleres (?). 3. Microxea, fusiform, sharply pointed, O'l by 0*004 mm. 
Colour. — The specimen is a dead skeleton. Size, 14 mm. in length by 7 mm. in 
width where widest, to 3 mm. where narrowest, and 6 mm. in height. 
Habitat. — Station 192, off the Ki Islands, south of Papua, September 26, 1874; 
lat. 5° 49' 15" S., long. 132° 14' 15" E.; depth, 140 fathoms; bottom, blue mud. 
Remarks. — The strongyloxea and microxea, marked as only doubtfully present, occur 
amongst the loose material detached by boiling in nitric acid ; so many other spicules of 
different kinds, evidently foreign to the sponge, are associated with them, that I doubt 
very much whether they should be included in the description. 
