THE SPONGES OF THE WEST-CENTRAL PACIFIC 133 



The skeleton consists, first, of ectosomal-type spicules as characteristic 

 of the genus Lissodendoryx. These are smooth tylotes, 3 fx by 230 /x in di- 

 mensions. The endosomal spicules are acanthostyles, but the pointed end 

 is so blunt that they give a brief impression of being acanthostrongyles. The 

 ends are more spiny than the middle of these spicules, and the ornaments are 

 more like small lumps than sharp spines. Their dimensions are approximately 

 5 ix by 165 fi. There are some typical arcuate isochelas, 25 fx long, as are 

 expected in the genus Lissodendoryx, and abundant sigmas, 20 /x in chord 

 length, also as typical of this genus. There are in addition abundant tricho- 

 dragmas, 0.3 /x by 35 /x in measurement. This is not expected in this genus. 



The species oxytes is set apart by a number of characteristics : the 

 trichodragmas, the distinctive purple color, and most of all its tendency to 

 penetrate. 



The specific name is derived from a Greek word meaning "penetration." 



Lissodendoryx calypta, new 



Text Figure No. 84 

 Plate VIII, Figure b 



This species is here represented by the following : 

 U.S.N.M. No. 22806, My No. N. Oil, here designated as type, collected on 

 June 5, 1946, by W. R. Taylor at Eniwetok Atoll in the lagoon 8 kilom- 

 eters north of the south anchorage by dredging at a depth of 35 meters. 

 This was near the very center of the lagoon and is in U.S.N.M. ac- 

 cession No. 172224. 



This remarkable sponge is a paper-thin incrustation which covers about 

 nine-tenths of the total surface of a handful of branches of the keratose 

 sponge Thorectopsamma mela. The covered sponge seems to have been 

 none the worse for its clothing. Its branches are about 1.5 cm in diameter 

 and project only about the same distance beyond their envelope at their grow- 

 ing tips. Evidently the Lissodendoryx grew about as fast as they and was 

 thin enough to permit ready passage of water through itself to the underlying 

 sponge. 



The color in alcohol is pale, the consistency is like cloth, but it is easily 

 torn. The surface is smooth and lipostomous. 



The sponge is extremely thin, so that there is no distinct separation as 

 to ectosome and endosome, although the skeleton comprises spicule categories 

 typical of the two locations. 



The skeleton consists of two sorts of megascleres and at least two sorts 

 of microscleres. The former comprise, first, hastate tornotes of the sort which 

 often characterize ectosomes and which are about 2 fx by 170 /x and, second, 

 acanthostyles, as to be expected in endosomes ; these latter are 4 ^ by 60 /i. 

 to 6 [x by 90 ix. There are arcuate isochelas of commonplace shape and of 



