THE SPONGES OF THE WEST-CENTRAL PACIFIC 73 



end in the isodictyal reticulation but, here and there, unites them into vague 

 tracts of one to three spicule rows only. In Specimen No. M. 389, some of 

 these tracts are so large that they reach a diameter of 20 /*. In this specimen 

 such fibers are about 100 /a apart, running perpendicular to the surface. The 

 spicules are commonly about 5 [x by 110 /a to 6 fi by 125 t<. in dimensions. A 

 few which are thinner, i.e., only 2 ti by 100 [x, are probably juvenile forms. 



This species may be sharply characterized by its remarkable pigment, 

 which not only imparts the vivid color to the sponge, but has stained a dark 

 mahogany color all the labels which were put with the specimen. Comment 

 was made that specimen M. 392 had an orange endosome; this may be ac- 

 counted for by the presence in the endosome of abundant Cyanophyceae, 

 which are conspicuous in the microscopic preparations of only this specimen. 

 On the other hand, the occurrence of bright orange embryos may indicate 

 that the exceptional color of No. M. 392 was associated with a reproductive 

 condition. Another distinctive feature of rotographura is the very fleshy 

 endosome. 



The species rotographura appears to be confined not merely to Likiep 

 Atoll but to only the eastern portion of its lagoon. Comment needs to be 

 made, however, upon the fact that many collections studied as representing 

 the Pacific area have been in dried condition. When dry, specimens of 

 Haliclona, Reniclona, and related forms lose many of the distinctive charac- 

 teristics which appear in life. Thus, specimens of this species may have 

 been in collections and may have been given names ; yet one would never be 

 able to tell from the specimens that they were conspecific with the species 

 here discussed. It must also be kept in mind that it may really be a unique 

 endemic form, as here opined. 



GENUS TOXICLONA new 



This genus is here established in the family Haliclonidae to have as 

 genotype the sponge described as Siphonochalina gaussiana by Hentschel, 

 1914, page 136. This species and this genus are characterized by haliclonid 

 architecture, with a spiculation of oxeas and toxas. 



No specimens of this new genus were found in the territory now under 

 discussion. The species gaussiana was antarctic. 



GENUS RENIERA Nardo 



Haliclonid sponges occur that are ramose, with oscules scattered on the 

 sides of the cylinders ; this is true of the type species of the genus Haliclona. 



Haliclonid sponges occur that are incrusting, with oscules scattered on 

 the surface. Such are here treated as in the subgenus Reniclona. Around 



