462 PROCEEDINGS OF THE NATIONAL MUSEUM vol.83 



Genus TETHYA Lamarck 



TETHYA AURANTIA (Pallas) 



This species is represented in the collection by U.S.N.M. no. 22234. 

 It occurs intertidally at Fort Randolph. It is spherical in shape and 

 was bright orange-yellow in life. The consistency is cartilaginous, 

 and the surface is coarsely tuberculate, with rounded tubercles 

 crowded closely together, each about 2 mm in diameter and height. 

 The megascleres are strongyloxeas about 25ju by 2500/li. The micro- 

 scleres include large spherasters about 55m in diameter and small 

 spherasters only about 9m in diameter. 



This cosmopolitan species was described by Pallas (1766, p. 357) as 

 Alcyonium aurantium. The Panamanian specimens do not differ in 

 any significant respect from the numerous ones found in all parts of 

 the world. 



Genus CINACHYRA Sollas 



CINACHYRA APION Uliczka 



This species is represented in the collection by U.S.N.M, no. 22229. 

 The one specimen was collected intertidally at Fort Randolph. It 

 was yellow in hfe. Its consistency is between cartilaginous and 

 mediocre. It is exceedingly hispid with a spicule plush 2 mm high 

 or more over the entire surface. The abundant openings, repre- 

 senting probably both inhalent and exhalent structures, are cavities 

 1 to 3 mm in diameter, rounded at the bottom of the concavity, 

 and so abundant that in many places they are only 3 mm apart. 

 The internal structure is strongly radiate, including numerous 

 oxeas, about 30m by 3 mm long, and protriaenes and anatriaenes 

 having rhabds of about the same size range as the oxeas. The 

 clads of these spicules diverge very widely, almost at right angles 

 to the main shaft, so that they do not differ greatly from ortho- 

 triaenes. The microscleres are small sigmoid spicules 10m in length 

 of chord. 



This species was described by Uhczka (1929, p. 43) from the 

 West Indies, to which locality it appears to be restricted. 



PLAKOOSA, new genus 



Diagnosis. — Family Halinidae. A genus having as spicules two 

 size ranges of very small, much modified tetraxon spicules, the 

 smaller of which resemble asters. 



Relationship is indicated to Plakortis Schulze, which does not 

 have the latter type of spicule, to Halina Bowerbank in which the 

 second type is an obvious strep taster, and closest of all to a common 

 West Indian sponge, Roosa zyggompha deLaubenfels (1934, p. 2), 

 which has somewhat similar megascleres, but not the microscleres. 



