198 ^^e Philippine Jommal of Science wis 



Subphylum SAKCODINA — Continued. 

 Class Actinopoda — Continued. 

 Subclass Radiolaria — Continued. 

 Division A. Porulosa — Continued. 

 Legion 2. Actipylea (Acantharia). — Here the pores are aggregated 

 in definite areas. The skeleton consists, usually, of twenty 

 spines of acanthin (strontium sulphate), which radiate from 

 the center of the organism in a regular order (MuUerian 

 law) . These spines may branch to form a latticed shell. 

 Order Actinellida. — There are more than twenty radial spines. 

 Haeckel names three families. Typical genus, Xiphacantha 

 Haeckel, 1862. 

 Order Acanthonida. — The twenty spines are all equal in size 

 and are arranged in regular order: four equatorial, eight 

 tropical, and eight polar. Haeckel names three families. 

 Typical genus, Acanthrovietron Miiller, 1855. 

 Order Spherophracta. — A complete fenestrated shell. Twenty 

 equal, quadrangular spines. Haeckel names three families. 

 Typical genus, Dorataspis Haeckel, 1860. 

 Order Prunophracta. — An ellipsoidal, lenticular, or doubly conical 

 shell is present. The twenty radial spines are unequal. 

 Haeckel names three families. Typical genus, Thoracaspis 

 Haeckel, 1860. 

 Division B. Osculosa. — The form is monaxonic. The pores of the 

 central capsule are limited to an area on the base, or to one 

 such primary basal area and two secondary apical areas. These 

 perforated areas of the central capsule are termed oscula. 

 Legion 3. Monopylea (Nassellaria) . — The skeleton is siliceous. The 

 central capsule consists of a single layer of chitin; it is sub- 

 spherical to ovoid and is perforated at one pole only. 

 Order Nassoida. — The skeleton is absent. Haeckel names one 



family. Typical genus, Nassella Haeckel, 1887. 

 Order Plectoida. — The skeleton is formed of three or more spines, 

 which radiate from one point below the central capsule or 

 from a central rod. Members of this order never form a 

 complete latticed skeleton. Haeckel names two families. 

 Typical genus, Triplecta Haeckel, 1881. 

 Order Spyroida. — A lower chamber may be added to the shell. 

 The skeleton consists of a sagittal ring and a latticed shell 

 that is furrowed in the sagittal plane. Haeckel names 

 four families. Typical genus, Dictyospiris Ehrenberg, 1847. 

 Order Stephoida. — The spines fuse to form one or more rings, 

 "which compose the skeleton. Haeckel names four families. 

 Typical genus, Lithocircus Miiller, 1856. 

 Order Botryoida. — The skeletons are similar to those in the or- 

 der Stephoida, but they have, in addition, another wing- 

 like process or lobe and one or more additional chambers. 

 Haeckel names three families. Typical genus, Lithobotrys 

 Ehrenberg, 1844. 

 Order Cyrtoida. — The skeletons lack the lobes or furrows, but 

 are in other respects similar to those in the order Botryoida. 

 Haeckel names twelve families. Typical genus, Theoconus 

 Haeckel, 1887. 



