THE SPONGES OF THE WEST-CENTRAL PACIFIC 173 



Other spots are obscured by much debris, especially flakes of mangrove 

 tissue from the nearby mangrove forest. There also were many diatoms 

 present. Even through the microscope the surface appeared to be liposto- 

 mous. Evidently the openings are quickly and powerfully closed. 



The ectosome and endosome of this species are exaggeratedly like those 

 of the family Axinellidae. There is a central axis about 3 or 4 mm in di- 

 ameter, consisting of spicules which are arranged longitudinally and are 

 packed rather densely together. Tracts or fascicular bundles of large spicules 

 protrude at right angles in all directions. The bundles are about 1 mm thick 

 and somewhat more than 2 mm apart. In the extensive interstices between 

 these fascicular bundles there are many smaller spicules in confusion and 

 much protoplasmic structure. Although obscured by foreign material and 

 protruding spicules, a thin protoplasmic dermis about 10 /x thick can be dis- 

 cerned over much of the surface. 



Study of the skeleton with a microscope reveals that a number of tracts 

 are only 100 /x in diameter. The spicules are all smooth styles, sometimes 

 being subtylostylote. These are of four size ranges. The largest, which 

 protrude away from the central axis and render the surface hispid, are about 

 14 fi in diameter and several mm long. Portions at least 3 mm long could be 

 found, but none of the longest ones were unbroken so that maximum lengths 

 must be surmised. The spicules packed in the central axis are a little smaller, 

 and those in the interstitial areas are still smaller. Others are as small as 2 /*, 

 by 156 jx in dimensions. 



There are about five other ramose species now in the genus Homaxinella, 

 and all of these are characterized by spicules much smaller than those in the 

 species phrix. The nearest in this regard is probably that first described as 

 Axinella axifera by Hentschel, 1912, page 418, from the East Indies. The 

 axis of this sponge was described as horny, however, and the spicules are only 

 19 ix by 880 /x at the maximum. 



The specific name is derived from the Greek word meaning "bristling." 



GENUS PARARHAPHOXYA Burton 

 Pararhaphoxya tenuiramosa Burton 



Text Figure No. 114 



This species is here represented by the following : 



U.S.N.M. No. 23062, My No. M. 442, and 



U.S.N.M. No. 23063, My No. M. 443, each collected August 3, 1949, by 

 diver in southwest Ponape in the province of Kiti, near Toletik Islet, 

 from a reef in the lagoon near the shore. The depth was 4 meters, 

 and the substrate in each case was dead coral. These two specimens 

 were collected almost side by side but were selected to show an extreme 

 variation in form and to allow contemplation of subsequent investigation 



