REPORT ON THE RADIOLARIA. 



CU1 



Legions. 



III. Legion (or Subclass) 



NASSELLARIA 



(Monopylea). 



[Osculosa monopylea.'] 



IV. Legion (or Subclass) 



PH.EODARIA 

 (Cannopylea). 



[Osculosa cannopylea.'] 



Sublegions. 



V. Plectellaria 



(Nassellaria palliata) 



VI. Cyrtellaria 

 (Nassellaria loricata) 



VII. Phseocystina 

 (PhcKo 



VIII. Phseocoscina 



(Plui'orlaria loricata) 



Orders. 



11. Nassoidea, . 



12. Plectoidea, 



13. Stephoidea, 



14. Spyroidea,. 



15. Botryodea, . 



16. Cyrtoidea, . 



17. Phaeocystina, 



18. Phaeosphferia, 



19. Phseogromia, 



20. Phaeoconchia, 



Typical Families. 



11. Nassellida. 



12a. Plagonida. 



126. Plectanida. 



13a. Stephanida. 



136. Tympanida. 



14a. Zygospyrida. 



146. Androspyrida. 



1 5a. Cannobotryida. 



156. Lithobotryida. 



15c. Pylobotryida. 



16<z. Monocyrtida. 



166. Dicyrtida. 



1 6c. Tricyrtida. 



16d. Stichocyrtida. 



| 17 a. Pheeodinida. 



j 176. Cannorrhaphida. 



| 17c. Aulacanthida. 



j' 18a. OrosphsDrida. 



^ 186. Aulosphserida. 



( 18c. Cannosphserida. 



( 19a. Challengerida. 



1 196. CastaneUida. 



( 19c. Circoporida. 



( 20a. Concharida. 



< 206. Coelodendrida. 



( 20c. Cffilographida. 



156. Formation of Species. The totality of similar forms, which we unite in one 

 species, and which in the earlier dogmatic systems was regarded as a category of absolute 

 value, possesses only a relative value like all other systematic categories ( 155). 

 According to the individual views of the systematist and the general survey which he 

 has attained of the smaller and larger systematic groups, the conception of a species 

 adopted in his practical work will be wider or narrower. In the present systematic 

 arrangement a medium extent has been adopted. It is shown that in the Radiolaria, as 

 in all other extensive groups of organisms, the constancy of the species is very variable in 

 the different groups. Many families of Eadiolaria are very rich in " bad species," i.e., 

 very variable forms, in which the process of the formation of species is seen in progress ; 

 such, for example, are among the SPUMELLARIA, the Sphserozoida, Stylosphserida, Phaco- 

 discida and Pylonida ; among the ACANTHARIA, the Amphilonchida and Phractopeltida ; 

 among the NASSELLARIA, the Stephoidea and Botryodea; and among the 

 PH^ODARIA, the Aulacanthida, Sagosphserida, Castanellida and Concharida. On the 



