STAUEOCALYPTUS ENTACANTHÜS. 197 



When fully grown, the paratangentiaLs, wliich are either paratropal 

 or regularly cruciate, measure 4 mm. in length and 65/^- in 

 thickness at l)ase. They may acc^uire a rough surface, due to 

 rounded microtubercles, while still remaining in the hypodernial 

 situation. But this apparently does not take place in all cases, 

 for among the oxypentactins already })rotruded as prostalia I have 

 found some with rough and others with perfectly smooth para- 

 tangentials. 



Diactins also enter into the composition of the hypodermal 

 strands though not in large numbers. These hypodermal diactius 

 are somewdiat variable in size and characters. While the larger 

 of them are indistinguishable from ordinary parenchymalia, others 

 are small, tubercled around the center and rough all over instead 

 of being so at the ends only. The latter kind might easily be 

 taken for derinalia, were it not for their association with unmis- 

 takeable hypodermal elements. 



The Jiypogastralia are diactins similar to those of the hypo- 

 dermal strands. 



The dermalia and gaslralia may be said to be essentially 

 like those of S. doivUngiy tubulosus and affinis. 



On the pentactinic dermalia, which are by far the predomi- 

 nant form, I have frequently observed a low prominence in the 

 place of the aborted distal ray. Length of rays, 180-200/'. 

 Earely stauractins and still more rarely diactins are met with 

 among the dermalia. 



With respect to the hcxactinic gastralia, it may l)e mentioned 

 that these are on the whole somewhat smaller than the same 

 spicules in either S. tubulosus or affinis, agreeing closely in this 

 respect with S. dowliugi. Length of rays, üö-loO /^. 



