188 THE SPONGES OF THE WEST-CENTRAL PACIFIC 



<c 



B 



Text Figure No. 125. Spicules of Hymeniacidon aldis, X 182. A: Sharply bent style. 



B : Commonplace style. 



normal specimen of Stylotella agminata in the family Suberitidae. Against 

 this possibility it may be stated that aldis has no fiber, the surface is not 

 Suberitid, and the spicules are very much thicker than those in agminata. The 

 genus Hymeniacidon stands in considerable need of revision, being at present 

 overburdened with species names. In general, the many species described 

 from North American and European waters have spicules much smaller than 

 those of aldis. The fairly numerous species described from the Indian Ocean 

 and East Indian region do have rather thick spicules. If more specimens 

 become available and further study is made, it may prove ultimately to be 

 necessary to reduce in synonymy not merely aldis but a number of others now 

 in the literature. 



The name aldis is selected primarily for euphony but is derived (by very 

 extensive alteration) from the Greek word aldaino meaning "to grow, wax 

 or thrive." 



Hymeniacidon dystacta, new 



Text Figure No. 126 



This species is here represented by the following : 



U.S.N. M. No. 22852, My No. M. 146, here designated as type, collected on 

 July 5, 1949 by a diver from the miniature lagoon at the southwest 

 corner of the main lagoon at Ebon Atoll. The substrate was dead coral. 



U.S.N.M. No. 22798, My No. N. 003, collected on April 25, 1946, by dredg- 

 ing 7 kilometers south of the west end of Bikini Island, in the lagoon 

 of Bikini Atoll at a depth of 50 meters. The collector was J. P. E. 

 Morrison. 



U.S.N.M. No. 22803, My No. N. 008, with the same collection data as the 

 preceding specimen. 



U.S.N.M. No. 22826, My No. N. 033 collected on July 11, 1946, by dredging 

 5 kilometers off Bikini Island in the lagoon of Bikini Atoll at a depth of 

 50 meters. The collector was J. P. E. Morrison. 



( 

 -I 



Text Figure No. 126. Spicule (tylostyle) of Hymeniacidon dystacta, X 781. The entire 

 spicule is shown, but in two parts. 



