PLATE XV. 



FIG. 



1, 2, 3, 4, 5, 6, 1. — Various curious forms of three-winged Astrommas (?) 

 Stephanastrum, or some allied shapes. Fig. 3 has a partial 

 representative in Ehrenberg's Hynieniastrum Pythagora?, Mik. 

 PI. XXXVI, fig. 31. In fig. 1 the three arms appear to be 

 hollow tubes of a sort of honeycomb : the extreme measurement, 

 .0211. The very remarkable border or edge to the sponge-like 

 webwork, is the nearest approach I have ever seen to the 

 rhombic frame (separated from the web) of the " Stephanas- 

 trum Pthombus" shewn on PL XXXVI of Mkrogeologie, fig. 

 33, and copied into so many works. 



8.— A delicately ornamented spicule (?) with still a small portion of 

 web adhering to it. AU these objects are from Mr. Browne's 

 slides. 



