1888.] MICKOSCOPiCAL JOURNAL. T 



at maturity, and Leidy cites Clarapede and Lachmann as vouching for the 

 same fact. The green mass in Heleopera is probably a collection of spores. 

 For illustrations of these points the student is referred to Leidy's work on 

 Rhizopods, plate xxxv, showing three successive views of the same pair of 

 individuals in so-called conjugation ; also plates xxxiii, xxix, xxvii, and 

 especially plate xxxix, fig. 35, which is almost a demonstration that the pi'o- 

 cess is not conjugation, but simple division. See also plate xl for division of 

 Aciinophrys, and plate xliv for Clathrulina and young. Carpenter may also 

 be consulted with advantage. See pp. 470, 471 for reproduction oi Pro- 

 tomyxa and VampyreUa, which though now ranked still lower than the 

 Rhizopods are so close to them (differing only in the absence of a nucleus, 

 and even that is said to have been found in Vampyrella) that they may lead us 

 to infer the like process for the higher members of the Protozoa. See also 

 p. 479 for reproduction of Microgromia, and p. 485 for that of Clathrulina 

 by a different process from that figured in Leidy. But the whole subject is 

 as yet very imperfectly understood, and it is a point toward which the ob- 

 server may well direct his attention. There is a chance here to make most 

 important discoveries, and everyone who studies the Rhizopods should make 

 this a special object of his investigations. The great difficulty I find to be the 

 lack of a perfect growing slide. I have tried several forms, but they are all 

 unsatisfactory, and one is obliged to trust to luck — to a happy observation 

 just at the right time. I have had splendid specimens of Heleopera under 

 observation lately, in which the spore-case was unusually well developed ; I 

 have even seen the protoplasm protruded and one or two of the green granules 

 with it, the protoplasm assuming spherical form with the granules inside ; I 

 have seen what appeared to be the spore-cases after they had been entirely 

 set free from the shell ; and if I had only had a proper growing slide I feel 

 sure the development might have been easily watched. If therefore any one 

 can help me in this line I shall take it as a favor. 



Having thus touched upon the main points of the life-history, we come now 

 to the classification, concerning which the authorities are not agreed. Carpen- 

 ter makes three divisions, the Mic. Diet, four, Leidy five, while Lankester, 

 in his magnificent article on the Protozoa in the last edition of the Eiicy. 

 Brit., and Huxley also, in his article on the Animal Kingdom, in the same 

 work, propose a system in which the Rhizopods as a distinct class find no 

 place, neither ' local habitation nor a name.' But, as this latter system is 

 ver}'^ recent and much more intricate, and is frankly confessed to be merely 

 tentative, I have thought it best to confine myself to the older method, as be- 

 ing more serviceable to us, since we are much more likely to have at hand 

 the works of the former three authorities. And if we leave out the last di- 

 vision of Leidy, as Carpenter has done, making the Monera a distinct class 

 of the sub-kingdom Protozoa, we shall find that these three authorities are 

 virtually in agreement, thus : — The Reticularia of Carpenter = the Forami- 

 nifera of the Mic. Diet, and Leidy ; the Heliozoa of Carpenter^ the Radio- 

 laria of the Micrographic and the Heliozoa, and Radiolaria of Leidy ; while 

 the Lobose of Car^>enter and the Mic. Diet. = the Protoplasta of Leidy. 

 And since Leidy is our great American authority, and the one most likely of 

 all to be studied by any of us, I have given his classification the preference, 

 omitting the last division, so that we have these four orders : — 

 I. The Protoplasta. 

 IL The Heliozoa. 



HL The Radiolaria. 



IV. The Foraminifera. 



These four fall again into two main subdivisions, founded on locality. 

 namely, the fresh-water and the marine Rhizopods ; the Protoplasta and the 



