450 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



This species was described as Suberites sulcatus by Thiele (1905, 

 p. 417) from the extreme southern end of South America. Burton 

 (1930, p. 334) also records it from the Antarctic and correctly trans- 

 fers it to the genus Psevdosuberites . There is no considerable point 

 of difference between the Panamanian specimen and those from the 

 sub-Antarctic and Antarctic. 



G.enus LAXOSUBERITES Topsent 



LAXOSUBERITES ZETEKI, new species 



Figure 42 



Holotype. — U.S.N.M. no. 22212, from Balboa, Canal Zone, on the 

 Pacific coast; no. 22227 is a specimen from the Caribbean. 



This is in some respects the species most characteristic of the 

 Panama coast, being found abundantly at each end of the canal. 

 The specimens are frequently large and massive, with digitate or 

 hemispherical projections, often as much as or more than 8 cm high. 

 The masses are frequently as large as a person's head. The color 

 in life is fundamentally an ochre-yellow; an exceedingly thin layer at 

 the surface, however, may be tinged with greenish or reddish color, 

 or, as in the case of specimens from the Atlantic end of the canal, 

 be almost completely covered with a brownish red. These colors 

 may be due to the presence of algal cells on the surface. The con- 

 sistency is weakly spongy or mediocre. The surface, aside from the 

 above-mentioned digitate projections, is somewhat tuberculate but 

 otherwise smooth and even, not at all hispid. The oscules are 

 exceedingly contractile. In living specimens they can sometimes 

 be made out, attaining a diameter of as much as 1 mm, but in pre- 

 served specimens they are often entirely or nearly invisible. A few 

 exceptional individuals were found in which the oscules remained 

 open, over 2 mm in diameter, and surrounded by a collar more than 

 2 mm high. These specimens grew where the currents were not 

 very strong. This variation in oscular condition is a result of environ- 

 mental stimuli and lacks taxonomical significance. The spicules in 

 the ectosome are densely packed, erect, with points out, but do not 

 differ significantly in size or shape from those in the endosome. 

 The interior is minutely cavernous to dense, with occasional meander- 

 ing canals about 2 mm in diameter. The flagellate chambers are 

 subspherical, about 20^ to 25^ in diameter. About them the mega- 

 scleres are strewn in confusion. No microscleres could be found, 

 all the spicules being tylostyles varying from about 3/i to 20/i by at 

 least 700/x in length, and how much more must remain problematical, 

 inasmuch as the largest spicules were always found broken. 



