W. LEUCKARTI. — SPICULATION. 289 



nature and structure in Regadrella phœnix (p. 274). In other 

 places the dermalia are usually much shorter— sometimes only 

 ahout half as long, the blade-ray being of about twice the length of 

 the hilt-ray. Thickness of rays at base 4 /^ in the slender-rayed 

 forms, but as much as 10 /^ in the more stoutly developed ones. 



The hilt-ray, 165-250/^ long, gradually thickens distally, 

 finally to contract again and to terminate in an acute or obtuse 

 point, rarely in a rounded knob. Thus, it is of a slender club- 

 like shape. In a large specimen of the spicule, the swollen part 

 may be 20/^ thick, i. e., about twice as broad as at the base. 

 The surfiice is rough on account of low scaly microtubercles 

 which gradually lose themselves toward the base of the ray. 

 The roughness may be obsolete, especially on the more slenderly 

 developed hilt- ray. 



The paratangential rays, 80-200 ix long, are usually slightly 

 broadened toward the end, which is sparingly microtubercled and 

 obtusely pointed. They are not always quite straight, nor of the 

 same length in the same spicule. 



The proximal blade-ray tapers towards the pointed and 

 faintly roughened end. It is not infrequently bent in adaptation 

 to the circumstances of its occurrence. 



As gastralia (PI. XIII, fig. 10) are to be considered pentac- 

 tins of medium or small size, found isolated and by no means 

 numerously on the inner surface of the stem-wall. The paratan- 

 gentials are usually 90-145 F- long and about 8 /^ thick at base, 

 while the distally directed, unpaired ray is about twice as long 

 or longer. All the rays are smooth except near the conically or 

 bluntly pointed end. A knob on the proximal side of the 

 spicular center represents the atrophied ray. Moore's statement 



