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PROCEEDINGS OF THE NATIONAL. MUSEUM 



VOL. 81 



6 mm or more, and are nearly uniformly broad throughout the entire 

 length, measuring 8ja to 20^ at the center. 



The hypodermalia and hypogastralia are mainly diactins; pent- 

 actins are not found. These hypogastral diactins are broader but 

 shorter than those of the hypoderm. They measure 16)u, to 40;(i 

 thick at the center and attain a length of 1.37 mm to 2 mm. Some- 

 times their spicular center shows a gentle annular swelling. 



Figure 11. — Aulosaccus solaster, new species : a, h. Dermal hexactins ; c, gastral hexactia ; 

 d, hemihexactinic form ; e, hexactinie form ; f, hemihexactinic form ; g, h, small hexac- 

 tinic form ; i, j, ox.vhexasler ; A;, mierodiscohexaster ; I, macrodiscohexaster. All X 225 



The dermalia are all hexactins (fig. 11, «, h) in which the proximal 

 ray is always longer than any of the other rays. They are of two 

 forms, one being occasionally intermingled with the others. In the 

 first kind, the length of the paratangentials is lOO^i to 132/i,; distal ray 

 is as long as the paratangentials or somewhat longer; length of 

 proximal ray, 121/a to 154/* ; breadth at base of rays, 20/i,. The length 

 of paratangentials in the smaller one is 68/* to Y3/i; the distal ray is 

 also as long as the j^aratangentials or somewhat longer; length of 



