650 SUMMARY OF CURRENT RESEARCHES RELATINO TO 
with great rapidity, even after having been kept more than a year in 
the cabinet. Ingestion of the food-material by the swarm-eells of 
Perichsena corticalis was observed similar to that already described in 
the case of Stemonitis fusca. The calcareous matter is discharged from 
the plasmode of Chondrioderma difforme immediately after it has taken 
the sporange-form. 
Mr. Lister supports the view of De Bary that the Mycetozoa should 
be placed in the animal rather than in the vegetable kingdom. He con- 
siders it probable that many forms hitherto considered as distinct 
species will ultimately be traced to a common parentage ; remarkable 
variation occurs in the progeny of a common parent, when the natural 
conditions are slightly altered by cultivation, in the structure of the 
calcareous wall of the sporange, in the degree of development of the capil- 
litium (or even in its presence or absence), in the colour and size of the 
spores, and in the colour of the membranous wall of the sporange, of 
the threads of the capillitium, and of the plasmode. The colour of the 
plasmode is described in between 40 and 50 species. 
Ingestion of Food-material by the Swarm-cells of Mycetozoa.* — 
Mr. A. Lister gives an account of observations on the ingestion of food- 
material by the swarm-cells of Chondrioderma difforme , Physarum Tussi- 
laginis, Stemonitis fusca , and other Mycetozoa, the food-material being 
chiefly fragments of Stereum hirsutum, and the bacilli which accompany 
its decomposition. The bacilli become attached to delicate pseudo- 
podes put out by the swarm-cells; the pseudopodes gradually con- 
tract and draw in the bacilli, which then become inclosed in vacuoles, 
where they are entirely absorbed, scarcely a trace of residuum 
remaining behind. Carmine was also greedily incorporated by the 
swarm-cells of Stemonitis , but not by those of Amaurochsete ; the ob- 
servation being thus opposed to that of De Bary, who states that the 
food is taken in during the swarm-cell condition only in a fluid state. 
The ingestion is frequently accompanied by a violent jerking movement 
of the swarm- cell. If inorganic matter w*as taken in, it was expelled 
after a longer or shorter period. The food material appears to be taken 
in only at the posterior end of the swarm-cell, and the refuse matter 
discharged from the same region. 
Protophyta. 
o. Schizopliyceee. 
Defensive Structure of Diatoms.^ — Dr. D. Levi-Morenos asserts that 
the nutritive value of diatoms to fishes and other marine animals which 
feed upon them is not so much their protoplasmic contents as the mucila- 
ginous envelope which covers them, many species passing uninjured and 
without being killed through the digestive tube. Their rapid passage 
is assisted by the fusiform and sinuous shape of many species of 
Cymbella, Synedra , Nitzschia, Navicula , Pinnularia , Pleurosigma , &c. 
* Journ. Linn. Soc. (Bot.), xxv. (1890) pp. 435-41 (6 figs.). Cf. this Journal, 
1888, p. 783. 
t Boll. Soc. Ital. Microsc., i. (1890) pp. 103-18; and Nolarisia, v. (1890) 
pp. 956-63. 
