THE SPONGES OF THE WEST-CENTRAL PACIFIC 



143 



GENUS DICTYOCIONA Topsent 

 Dictyociona eurypa, new 



Text Figure No. 91 



This species is here represented by the following : 

 U.S.N.M. No. 22922, My No. M. 228, here designated as type, collected 

 September 1, 1949, by diver from Iwayama Bay near Koror in the 

 Palaus. The depth was 2 meters, and the substrate was dead coral. 



This species is incrusting, about 4 mm thick. It was very common 

 in this vicinity and completely covered a huge dead coral head. 



The color in life was a peculiar brown, like that of coffee with milk. 

 This was true of both the interior and exterior. The consistency was soft. 



The surface is smooth. The pores are about 70 /x in diameter and only 

 120 p. apart. The oscules are 7 mm in diameter and 12 mm apart, charac- 

 terized by a raised rim about 1 to 3 mm high around each oscule. 



The ectosome is densely protoplasmic and blends into the very fleshy 

 endosome. The spicules at the surface are erect and bristling but elsewhere 

 are in considerable confusion. 



The skeleton consists of subtylostyles with heads lightly spined. These 

 vary from 4 /x by 115 /x to 6 [x by 290 [x in dimensions. The microscleres 

 include very numerous typical, strongly bent toxas, 30 [x to 54 ti in length. A 

 single filiform toxa was discovered, 0.3 /x by 120 /x. This is probably foreign. 

 There are two types of palmate isochela present: the larger ones 19 \x long 

 and the smaller ones only 4 ti long. 



The species eurypa is distinctive for its peculiar color. The only other 

 Dictyociona with megascleres very much like those of eurypa was described 

 as Eurypon acanthotoxa by Stevens, 1916, page 238, from deep water near 

 Ireland. Stevens also described a species as microchela, but its chelas were 

 not nearly so small as these amazingly small ones of eurypa. On the other 



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Text Figure No. 91. Spicules of Dictyociona eurypa, X 782. A: Larger tylostyle; the 

 entire spicule is shown, but in two parts. B: Smaller tylostyle. C: Three of the toxas. 

 D: Palmate isochela of normal size, side and front views. E: Phenomenally small 



palmate isochela. 



