406 PROCEEDINGS OF THE XATIONAL MUSEUM. vol.37. 



The skeleton spicules are slender, smooth, sharply pointed at either 

 end, and nearly straight. They measure on an average 0.384 mm. 

 in length and 0.016 mm. in greatest transverse diameter. 



The long gemmule spicules (birotulates) are much longer than the 

 short ones and have slender, straight, almost smooth shafts with only 

 an occasional spine. Their rotulse consist of a circle of curved hooks 

 joined together at their base. The short birotulates have stouter 

 shafts, \vhich are profusely, irregularly, and somewhat strongly 

 spined. Their rotidae are not so markedly convex when viewed in 

 profile as those of the long birotulates; they are somewhat irregu- 

 larly but narrowly and deeply serrated, the incisions being often 

 arranged in groups. The long birotulates measure on an average 

 0.188 mm. in length, their rotulse being 0.028 mm. in diameter. The 

 corresponding measurements of the short birotulates are 0.06 and 

 0.028 mm.; but spicules of intermediate lengths occur. 



Free spicules resembling those of Ephydatia plumosa are fairly 

 abundant. They consist of a variable number of straight and irregu- 

 larly roughened shafts meeting at a common center. The shafts are 

 slender and often very numerous; tlieir tips are either pointed or 

 blunt, sometimes minutely globular; often one axis is stouter than 

 the others. 



The gemmules are large and spherical. Each has a single very 

 small aperture, which is provided with a short, straight, foraminal 

 tubule. 



Habitat. — Pinto Creek, Kinney County, Texas (Albert Turpe coll.). 



The free spicules of this species are as characteristic as those of 

 Ephydatia plumosa, which they resemble in some respects. In both 

 species they are very minute. 



