312 SUMMARY OF CURRENT RESEARCHES RELATING TO 



Protozoa. 



Fine Structure of Test of Arcella.* — J. A. Cushman and W. P. 

 Henderson find that the test of Arcella vulgaris is far from the simple 

 hexagonal structure figured by Leidy and other authors. The hexagons 

 have no sides in common ; three adjacent sides of three neighbouring 

 Areas inclose a small triangular space. These interpolated triangles are 

 not solid portions of the network, but themselves contain areoles of sub- 

 triangular outline. These are depressed areas in the network similar, 

 except in point of size and shape, to the hexagonal areas. Diagram- 

 matically the network may be conceived as formed of straight lines in 

 three sets of parallels, the lines of each set making an angle of sixty 

 degrees with those of the two other sets. Moreover, new columns of 

 hexagonal areas are during growth added or interpolated among the 

 previous ones. These new columns may be added in any of the three 

 directions conforming to the directions of the three sets of parallel lines 

 already referred to. 



Cultivation and Pathogenesis of Amoebae. f—W. E. Musgrave and 

 M. T. Clegg, publish an important paper on this subject. The most 

 interesting question dealt with is the property possessed by apparently 

 isaprophytic amoeboe from the outside world, by virtue of which they 

 become so modified by successive stages and changes in their environ- 

 ment or by symbioses that they become true parasites for monkeys, 

 guinea-pigs, and human beings. Numerous facts in the biology of 

 amoebae are communicated, and it has been found difficult to systematise 

 the points in such a way as to justify classification of species. Such 

 work is regarded as at present premature. The authors, therefore, 

 question the conclusions of Schuudinn and others regarding the existence 

 of a non-pathogenic Entammba coli and a pathogenic E. histolytica. In 

 xjultures, single species are often found which possess a combination of 

 some of the features which have been described as distinctive for different 

 species. 



Variability of Commensal Forms of Opercularia.J — E. Faure- 

 Fremiet calls attention to the variability of these Yorticellids which occur 

 -as commensals on Xotonecta, Corixa, Dytiscns, and other aquatic insects. 

 Being thus removed from the stringency of natural selection, they show 

 greater variability — like domesticated animals — than related non- 

 commensal forms. 



Studies on Peridine9e.§ — Y. Dogiel has studied a number of 

 Mediterranean forms with especial reference to their reproduction, e.g. 

 Oymnodinium lunula, G. spirale, var. obtusum, and five new species, 

 G. roseum, G. affine, G. parasiticum (in the eggs of a Copepod) 

 G. ca'Tuleum, and Foucketia armata. 



New Species of Giardia.|| — J. Kunstler and Ch. Gineste describe 

 Giardia alata sp. n. from the intestine of tadpoles taken near Paris. It 



* Amer. Nat., xl. (1906) pp. 797-802 (5 figs.). 



t Philippine Journ. Sci., i. No. 9 (1906) pp. 909-50 -(5 pis.). 



; C.R. Soc. Biol. Paris, Ixii. (1907) pp. 153-5. 



§ MT. Zool. Stat. Neapel, xviii. (1906) pp. 1-45 (2 pis.). 



jl Comptes Rendus, cxliv. (1907) pp. 441-3 (1 fig.). 



