THE SPONGES OF THE WEST-CENTRAL PACIFIC 79 



tion, there are definite ascending fibers which come up to the tubercles or 

 conules of the surface. These are fascicular, as though made out of many 

 of the smaller fibers, but attain a total diameter of only some 100 fi. 



This species is put in Cribrochalina with some misgivings, as that genus 

 is ordinarily cup-shaped or funnel-shaped, with concentric lines on the in- 

 terior. It is not very fruitful to search the literature for possible earlier de- 

 scriptions of this species, because of the frequency with which older workers 

 considered it sufficient to mention that a sponge was tubular or cup-shaped 

 without giving such details, now known as important, as the surface structures 

 and consistency. At the present time, at least five genera are characterized 

 by just such external shape as that exhibited by olemda. This species may 

 be described as being peculiar for the fascicular nature of the ascending 

 fibers, for the fact that the cloacal rim does not flare outward, and for the 

 peculiar and beautiful color. 



The name which is here selected is the native (Palau) appellation for 

 this particular species of sponge. 



GENUS XESTOSPONGIA de Laubenfels 

 Xestospongia sapra, new 



Text Figure No. 48 



This species is here represented by the following: 

 U.S.N.M. No. 23074, My No. M. 454, here designated as type, collected 



August 10, 1949, by diver at the west side of Moen Islet in the Truk 



lagoon. The depth was less than 2 meters, and the substrate was dead 



coral. 

 U.S.N.M. No. 23020, My No. M. 318, collected June 21, 1949, by diver 



at the north side of the lagoon near Matien Islet at Ailing-lap-lap Atoll. 



The depth was 5 meters, and the substrate was coral, perhaps living or 



perhaps dead. 



This species also is represented, although not in the present collection, 

 by U.S.N.M. No. 22733 which was collected at Yap in the summer of 1946 

 by R. W. Hiatt. 



This species appears to be moderately common throughout the whole 

 Truk lagoon ; other specimens were observed in Lemotol Bay in the western 

 portion. This species was also collected in Yap, as noted above, and was 

 described by de Laubenfels, 1949, page 126, on the basis of only a small 

 specimen brought back by Professor Hiatt. In this reference, it was dubi- 

 ously identified as Xestospongia cxigua, which was first described as Petrosia 

 exigua by Kirkpatrick, 1900, page 139, from the East Indian region. Com- 

 ment was made as follows: "If it were better known, other differences might 

 be revealed, demanding a different, perhaps new, name for the Yap species." 



