ZOOLOaY AND BOTANY, MICROSCOPY^ ETC. 247 



multinuclear at a later stage. New Eadiolaria have been discovered, 

 which, agreeing in the specific characteristics of the skeleton, are 

 some monozoic and some polyzoic. The Monocyttaria and Poly- 

 cyttaria of Miiller are, therefore, no longer to be regarded as important 

 divisions. 



The objections lately raised by Brandt to the importance of the 

 character of the presence of a central capsule cannot be substantiated, 

 and Hackel is of opinion that this author's views have been based on 

 too narrow an area of investigation. On the other hand, yellow cells 

 have not the importance that was once attributed to them ; " they are 

 in no way necessary for the nourishment of the Eadiolaria, though 

 they may be important agents in the matter." 



The four orders now recognized are the Acantharia, Spumellaria, 

 Nassellaria, and Phseodaria ; they are distinct monophyletic groups, 

 and Biitschli was right in laying stress on the fact that the compli- 

 cated phylogenesis of this section, so rich in specific forms, is a strong 

 argument in favour of the doctrine of descent, and that " in this way 

 those painstaking investigations of the microscopic world (which 

 many 'exact physiologists' consider mere morphological trifling) 

 come to be of real importance." 



The Acantharia, which never have a true silicious skeleton, cor- 

 respond on the whole to the AcanthometraB of J. Miiller ; the 

 ancestral form of the order appears to be Actinelius (first described by 

 Hackel in 1865), and it may be supposed to have arisen from 

 Actinosphcerium by the hardening of the firmer axial fibres in the 

 radial pseudopodia of the latter into radial spicules. 



The Spumellaria are equivalent to Hertwig's Peripylea, Thalassi- 

 collea, and Sphserozoea, and are all referable to Actissa, in which 

 there is neither an extra- nor an intra-capsular alveolus ; it is, perhaps, 

 the ancestral form of all the Eadiolaria. 



The Nassellaria (Monopylea of Hertwig) are characterized by 

 having a simple area of pores at one pole of the axis of the capsule ; 

 the ancestor is to be found in Cystidium inerme, which is distinguished 

 from Actissa by this restriction of the pores. 



The fourth group are better called Phaeodaria than Pansolenia 

 (Hackel) or Tripylea (Hertwig), as the only character in common is 

 the possession of the peculiar phseodium — a voluminous dark body of 

 pigment, which lies excentrically outside the central capsule, while 

 the latter has a double membrane and a radiated operculum. The 

 ancestor is the skeletonless PhcBodina. 



The systematic survey of the families concludes with a table of 

 the differential characters of the four orders, a " conspectus ordinum 

 et familiarum," and a hypothetical ancestral tree of the Eadiolaria. 



Bohemian Nebelidse.* — K. J. Taranek describes the structure of 

 the shell and inner envelopes and of the soft parts of these Ehizopoda. 

 He finds they form a transition in their shell-characters from the 

 Difflugiidce to the Euglypliidce. The shell is always more or less 

 laterally compressed. Besides the species in which the shell is con- 



* Abh. Bohra. Gesell. Wiss., xi. (1882) 55 pp. (5 pis.). 



