1896.] 



MICROSCOPICAL JOURNAL. 



97 



and a half times as long as the diameter of the phacoid 

 shell, and in the outer part about two-thirds as broad as 

 the latter, at the base about one third as broad ; their 

 rounded distal end armed with a strong pyramidal termi- 

 nal spine. Patagium incomplete, enveloping only the 



basal half of the arms, with five rectilinear parallel rows 

 of chambers forming a square. 



Dimensions. — Diameter of the phacoid shell 0.09 ; of 

 the outer medullary shell 0.045, of the inner 0.015 ; length 

 of the arms 0.25 ; greatest breadth, 0.075. 



Habitat — Fossil in the rocks of Barbados. 



Starch-Grains. — To recognize starch-grains, the best way is 

 to place a drop of dilute aqueous solution of iodine in iodide of 

 potassium in the water on the slide ; the starch is colored 

 blue. Of course, the polariscope may be used instead, but the 

 first process is very convenient, as it gives a blue color, and 

 the polariscope can be used as a confirming test. — The Interna- 

 tional Journal of Microscopy. 



