88 THE AMERICAN MONTHLY [Mch 



zoa,which are very common in warm seas. Thong-h broug-ht 

 up abundantly by the tow-net when collecting- in such re- 

 g-ions, they are perhaps somewhat less familiar, at least to 

 inland microscopists, than those other, more highly devel- 

 oped and more showy radiolarian g-roups which are roug-h- 

 ly classified and highly admired as "Polycystina." It will 

 be noticed that these are composite forms,of which the nu- 

 merous g-lobular zooidsareof the familiar radiolarian type, 

 but whose skeleton has not attained a g-reater dig-nity or 

 utility than that of a few slender, branching, silicious spic- 

 ules (sugfgestive, in g-eneral appearance, of some spong-es) 

 that surround the individual zooids, and protect them more 

 or less, in lieu of the comparatively massive and elaborate 

 "silicious skeletone" of the nearly related Polycystina 

 g-roups. The form and arrang-ement of the delicate and 

 beautiful spicules is best seen with a stereoscopic binocu- 

 lar (as Wenham's) and a ^rds or low-ang-led 4-lOths obj. 

 The "punctate" appearance of the g-lobules, which may 

 well have given rise to the specific name, is readily seen 

 with the same powers. If using- a ^th or l-5th, which is 

 seldom advisable, use only those of low ang-les and long- 

 working- focus, and use with very g-reat care ; as the speci- 

 men is thick, and many a J^^th would destroy the mount be- 

 fore focusing- through the object. — R. H. Ward. 



Midrib of Leaf of Strelitzia. — This section is from the 

 midrib portion of the leaf of a south Africa monocotyledo- 

 nous plant of the banana family. It is specially interest- 

 ing- for the g-ig-antic size, especially antero-posteriorly, of 

 some of its fibrovascular bundles ; also for the very larg-e- 

 celled, frail, thin-walled and loosely-packed parenchyma, 

 which has been unable to fill, even with that poor tissue,all 

 the area of the section, but has left larg-e air-spaces, be- 

 sides a liberal suply.of the ordinary ducts, and of g-iant size. 

 The vacant spaces occupy, from a quarter to a third of the 

 whole area. All these peculiarities are evidently due to the 

 rapid growth, especially in thickness, of this member ; such 

 exuberance of g-rowth being- well-known in the banana plant 

 and other members of the same family. There will be no- 

 ticed, also,the very highly differentiated and perfect though 



