110 PROF. G. S. WEST OK lEESHWATER EHIZOPODS 



invariably near their broad bases. The same is true of Cien- 

 kowski's Nuclearia ; but in several other genera which were 

 included in the ' Proteomyxa,' such as Protomyxa, Haeckel, and 

 Biomyxa, Leidy, the pseudopodia are anastomosing and often 

 very irregular ; they are bent and of variable width, exhibiting 

 none of the rigidity shown by the straighter pseudopodia of 

 Vampyrella or Nuclearia. The entire animals can be likened 

 unto a Gromia without its shell, whereas such is not the case in 

 Vampyrella or Nuclearia. 



The nuclei of the different forms of Ehizopods are very similar 

 and exhibit little variation in structure. The characters of the 

 nucleus are to my mind of much less importance in these 

 animals than might at first be imagined, and are of little 

 classificatory value. It is difficult to see how such a uniformity 

 of character as is exhibited by the nuclei of Ehizopods could be 

 utilized as a basis of classification. The nucleus may also be 

 absent in some species of a genus, although present in others 

 (cf. CocJiliop odium oninutuni). 



Considering the foregoing facts, it appears advisable to remove 

 the two genera Vampyrella and Nuclearia from the ' Proteo- 

 myxa,' chiefly on account of the nature of their pseiidt)podia, and 

 place them in a separate order of the class Ehizopoda — the order 

 ' Yampyrellida-' *. By the establishment of this order the fresh- 

 water Ehizopods fall under four orders, which are characterized 

 as follows : — 



Order 1. Proteomyxa. Nude Ehizopods which in the amoe- 

 boid condition possess an irregular mass of body-proto- 

 plasm, often reticulate, and anastoming pseudopodia of 

 considerable irregularity. 



e. g. Biomyxa, Leidy ; Gymnophrys, Cienk. 



Order 2. Yampyrellida. !Nude Ehizopods which in the 

 amoeboid condition possess a body-protoplasm of more or 

 less definite form, frequently globular or often elongated ; 

 with straight attenuated pseudopodia, often branched at 

 the base. 



e. g. Vampy^^ella, Cienk. (inch LeptopJirys, Hertwig 

 and Lesser) ; Nuclearia, Cienk. (incl. Seliophrys, 

 Greefl"). 



* Cf. G-. S. West, " Some British Freshw. Rhiz. and Heliozoa," .Tourn. Linu. 

 Soc, Zool. xsviii. 1901, pp. 308 & 333. 



