446 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



eter, and have about them raised collars over 2 mm high. The 

 endosome is an isodictyal reticulation of oxeas about Q/x by 140/x, 

 among which occur toxifomi microscleres 2fj, by 80^. 



This specimen differs in no significant respect from that Arctic 

 species described as Gellius proximus by Lundbeck (1902, p. 70). 

 It is noteworthy that several of the species occurring near Panama 

 City, less than 10° from the Equator, should have as their closest 

 relatives Arctic or Antarctic species. 



ZETEKISPONGIA, new genus 



Diagnosis. — Family Phorbasidae. Structure more reticulate than 

 plumose; special diactinal ectosomal spicules associated with special 

 diactinal endosomal ones of another sort; arcuate chelas and sigmas 

 for microscleres. 



Genotype. — Zetekispongia zonea, new species. 



The generic name is given in respect to the eminent zoologist, Dr. 

 James Zetek, of the United States Department of Agriculture, 

 Balboa, Canal Zone. 



ZETEKISPONGIA ZONEA, new species 



Figure 40 



Holotype.— V.S.N. M. no. 22215. 



The species is also represented in the collection by U.S.N.M. no. 

 22223. It was found abundant intertidally on the rocks of Taboga 

 Island, near the Pacific entrance to the Panama Canal. The color in 

 life was a characteristic reddish orange, wliich fades httle in preserva- 

 tives; this is quite unusual. The consistency is soft, slightly spongy. 

 The surface is coarsely tuberculate, with lumps about 1 mm liigh and 

 several millimeters wide, but otherwise comparatively smooth. There 

 is a conspicuous detachable dermal specialization composed of tan- 

 gentially arranged spicules and underlain by extensive subdermal 

 cavities. The rare oscules are approximately 1 mm in diameter, very 

 unevenly distributed, and apparently missing from some specimens, 

 which is doubtless correlated with the fact that the sponge grows 

 where the v/aves sweep back and forth, creating almost constant 

 strong currents. The endosome bears some resemblance to bread in 

 structure; it is much like many specimens of Myxilla and Lissoden- 

 doryx. There is some tendency to an isodictyal reticulation, which is 

 obscured by the fact that each side of each mesh is composed of many 

 instead of only one spicule. There are occasionally vague tracts, of 

 several rows of spicules, reaching a diameter of approximately SOju. 

 The special dermal spicules are tylotes, 4iu by 200/x to 5/i by 170^^. 

 The endosomal spicules are oxeas 9^ by 210/^ to llju by 215/x. There 

 are two sizes of arcuate isochelas for microscleres, but neither is 

 typically arcuate. The larger type, approximately 36/i long, some- 



