G. GENERAL NATURAL HISTORY AND ZOOLOGY. 345 



sibly may have something to do with that meteoric dust 

 which is being continually rained upon us from the spaces 

 of the universe. 12 A, July 13, 1876. 



CEPHALOSIPHOX AND A NEW INFUSOKIAN. 



Dr. C. T. Hudson concludes that the Gephalosiphon is a 

 genuine Melicertan, forming its tube from early youth, and 

 is not a temporarily incased Fhilodine^ as had been supposed 

 from having only one antenna. The new infusorian is named 

 Archimeclea remex, so called from its frequently assumed 

 corkscrew shape, and from its rows of cilia used as banks of 

 oars. The full-grown Archimedea is about one ninetieth of 

 an inch in length, with a tube of one twenty-fifth of an inch, 

 more or less, in length. It was found attached to Anacha- 

 ris alsinastrum. The tubes are exceedingly slender, and 

 readily deserted upon the least disturbance. They are, of 

 course, far too long for its inhabitant, which, as a rule, lives 

 in the top of it, though occasionally it backs down near- 

 ly to the bottom. Monthly Microscopical Journal^ October^ 

 1875. 



THE FRESH-WATER RHIZOPODS. 



A larsie number of contributions to our knowledixe of 

 "Fresh-water Rhizopoda" have recently appeared in the 

 Archiv fur Mikroscopische Anatomic^ and we condense the 

 following from a very complete resume by Mr. William 

 Archer, who has long been known as an indefatigable stu- 

 dent of these lively organisms. As for the name Rhizopodci^ 

 taken from the resemblance of the pseudopodia to the roots 

 of a tree, it is manifestly inapplicable to the broad-lobed 

 processes of a Difflugia or Arcella^ and quite so to the flow 

 and current of the body of an Amoeba^ or the rotating mo- 

 tion of a Ilyalodiscus. Hertwig and Lisser have proposed 

 the name Sarcodina (Sarcode organisms), with a division 

 into two groups, Monothcdamici and Ileliozoa^ and Mr. 

 Archer's resume^ so far as published, relates principally to 

 the latter. 



The Rhizopods in question have been termed "Fresh- 

 water RadiolciriaP Haeckel calls them Ileliozoa^ consider- 

 ing them as unicellular organisms, all the true (marine) lla- 

 diokiria being multicellular, and, again, as not possessing a 



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