PANAMA SPONGES — DE LAXJBENFELS 455 



triaenes with rhabds about SO/x by 3,000/x. Among the microscleres, 

 in addition to the sterrasters, there are euasters lO/x to 15ai in diameter 

 and very small spherasters, mostly centrum, the entire spicule only 

 about Zn in diameter. 



The last-mentioned type of microsclere is one of the most character- 

 istic features of Geodia gibberosa, which was described by Lamarck 

 (1815, p. 334) from the West Indian region, of wliich it is very charac- 

 teristic. 



Genus OSCARELLA Vosmaer 



OSCARELLA LOBULARIS (Schmidt) 



This species is represented in the collection by U.S.N.M. no. 22206. 

 It was found growing (as usual) as a thin encrustation on rocks in the 

 intertidal zone at Panama City on the Pacific side of the isthmus. In 

 life it is transparent and drab, consistency mediocre, surface smooth 

 and even. The oscules and pores were not optically evident. The 

 flagellate chambers are spherical, 25m in diameter. 



This aspiculous, askeletal, interesting species is probably cosmo- 

 politan, although nowhere abundant. It was first described as 

 Halisarca lobularis by Schmidt (1862, p. 80). It is difficult to find any 

 basis for separating those Oscarellas found in other parts of the world 

 from the original European species with which they may indeed be 

 genuinely conspecific. The Panama specimens are quite typical. 



DESCRIPTION OF ATLANTIC COAST SPECIES 



The six species found also at the Pacific end of the Panama Canal — 

 Haliclona coerulescens, Adocia cinerea, Halichondria panicea, Laxosu- 

 berites zeteki, Placospongia intermedia, and Geodia gibberosa — are not 

 repeated here. 



Genus SPONGIA Linnaeus 



SPONGIA BARBARA Duchassaing and Michelotti 



This species is represented in the collection by U.S.N.M. no. 22230. 

 It is a subspherical mass, black exteriorly and dull ochre in the endo- 

 some. The consistency is exceedingly spongy. The surface conules 

 are not quite 1 mm high and about 1 mm apart. The oscules, about 

 3 mm in diameter, are raised, with slight collars about them. The 

 flagellate chambers are spherical, about 20/x in diameter. The com- 

 mon fiber that makes up the customary dense reticulation is 30/^ in 

 diameter. The general structure is that of the common sponge of 

 commerce, known as the "yellow." 



Hyatt (1877, p. 515) records what he calls Sjjongia lignea from 

 Pearl Island, Panama Bay. This is inadequately described because 

 of the poor condition of Hyatt's material. 



