134 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



<Jt 



B "%^r D 



Text Figure No. 84. Spicules of Lissodendoryx calypta, X 781. A: Ectosomal tornote. 

 B: Endosomal acanthostyle. C: Larger isochela. D: Smaller isochela. 



two distinct size ranges — the larger 22 /x and the smaller only 10 /x long. I 

 was unable to find any sigmas or other microscleres. 



This species is set off by its distinctive shape. Very few species of 

 Lissodendoryx lack sigmas ; very few have the endosomal styles covered 

 with spines. None has the peculiar combination found in calypta. 



The species name is derived from the Greek verb "to envelop," refer- 

 ring to the strange habitus of this sponge. 



FAMILY PSAMMASCIDAE de Laubenfels 



GENUS PSAMMASCUS Marshall 



Psammascus ceratosus (Kirkpatrick) de Laubenfels 



Text Figure No. 35 



This species is here represented by the following: 

 U.S.N.M. No. 22893, My No. M. 193, collected August 3, 1949, by diver 

 in western Ponape near Tavak passage from a reef barely inside the 

 lagoon. The depth was 3 meters, and the substrate was dead coral. 



The shape of this species is incrusting. The specimens from Ponape are 

 less than 1 mm thick ; but they give the superficial appearance of representing 

 an enormous ramose sponge, because they completely cover a large bush of 

 dead coral of the sort known as "elkhorn" (probably Acropora). 



The color in life was a dull rose pink, with a distinctive opaque appear- 

 ance, due to the presence of much sand in the ectosome. The endosome in 

 contrast was bright vermillion and more nearly translucent. The consistency 

 was colloidal, the sponge being held together chiefly by its dermis. The 

 interior was a decidedly soft sol. 



The surface is fundamentally smooth, but marked by very conspicuous 

 grooves, which are often about 2 or 3 mm apart and 4 or 5 mm to 15 or 20 

 mm long, undulating and occasionally branched but not arranged in definite 

 river-system patterns. The pores apparently are arranged along these 



Text Figure No. 85. Spicules of Psammascus ceratosus, X 781. A: Oxea. B: Sigma. 



