24 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



as being ramosa only with considerable hesitation. Because of the small 

 size and agreement in internal characteristics, it is considered preferable to 

 identify them thus rather than to erect a new species, and certainly they 

 cannot be placed readily in any other existing species with greater confidence 

 than in ramosa. 



The color in life was ochre to olive brown, with a somewhat paler but 

 similarly tinted endosome. The consistency was very toughly spongy, flex- 

 ible, but extremely hard to cut, as is true of all members of this genus. 



The surface is conulose, covered with conules 1 to 2 mm high and 3 to 5 

 mm apart. The pores are approximately 100 /;, in diameter and about 300 /x 

 apart, center to center. The oscules cannot be found; therefore, one must 

 surmise that some of the small openings may be exhalant, as well as others 

 being inhalant. 



The ectosome is a thin, tough dermis. The endosome is quite typical of 

 the genus, with abundantly crowded spherical flagellate chambers about 30 /x 

 in diameter and with an obvious fibro-reticulation also present. 



The skeleton consists of ascending fascicular tracts of fibers, 200 /x and 

 more in diameter. The constituent fibers which make up these fascicles are 

 about 80 [j. in diameter, and the connective fibers may be a little smaller, say 

 50 fx in diameter. All of them contain more or less foreign debris. There 

 are also very numerous Ircinia filaments present, only about 2 /x in diameter. 

 It is noteworthy that in this species, both as collected in Ponape and in Koror, 

 there are present, along with the undoubted Ircinia fibers, slightly larger 

 strands containing scattered round greenish bodies that resemble chloroplasts. 

 In other words, this species also apparently contains symbiont algae. It is 

 very easy to surmise, when studying sections of these sponges, that the 

 Ircinia filaments represent partially digested and chemically altered algal 

 strands. 



Ircinia ramosa was described as H ircinia ramosa by Keller, 1889, page 

 345, and transferred to Ircinia by de Laubenfels, 1948, page 73. It is char- 

 acteristic not merely for its ramose form but for the very slender filaments, 

 similar to those which are present in these sponges from Micronesia. The 

 type specimen was from the Red Sea, but the species may be circum-equa- 

 torial, as it is recorded by de Laubenfels, 1934, page 24, from the West 

 Indian region. In color and in every other respect the Palau specimens are 

 quite typical of those found in other parts of the equatorial oceans. 



Ircinia halmiformis (Lendenfeld) de Laubenfels 



Text Figure No. 12 



This species is not here represented by any specimen. In the summer 

 of 1948, however, it was collected by Dr. T. E. Bullock within the region 

 here discussed. He collected two specimens from Bikini Atoll in the Mar- 



