246 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
these saddles being thrown across one another with their concave sides 
facing but not touching each other, so as to leave space for the soft living 
contents of the diatom. The connective zones, as in other diatoms, 
telescope one over the other, and unite the two valves by their outer 
margins. Having to follow the curvatures of two valves bent in oj>posite 
directions, they thereby acquire a remarkable zig-zag or undulating 
appearance, which at first sight is often somewhat difficult of interpreta- 
tion, especially when complicated with the reduplication of the cells. 
All the other characteristics of the genus are those of the family Suri- 
rellse, to which it clearly belongs. 
Mr. Deby gives the following definitions of terms : — Marginal rays 
or simply rays are the radiating lines (called by others “ costas ” or 
“ canaliculi ”), which, starting from the outer margin of the valves, 
converge towards the interior of the disc. These rays may be simple , 
which is tho commonest occurrence, or they may be moniliform, consti- 
tuted by beads either in single or double rows, or they may be imfundi- 
buliform, having the outline of a funnel with its lengthened outlet. The 
upper broad jrortion he calls the funnel, the slender part the stem. The 
central portion of tho valve inside the internal termination of the rays is 
the area ; it may be smooth and hyaline, or it may be striate or dis- 
tinctly punctate or dotted, the dots forming regular lines or else being 
irregularly scattered. In one division of the genus the area becomes 
reduced to a central median linear blank space, or to a simple elongated 
line. This is called the “ raphe” or “pseudo-raphe ” ; it shows neither 
the central nor the terminal nodules of the Naviculse proper. All lines, 
bars, or smooth striae on the area, the author calls the strise, in contra- 
distinction to the “ rays ” which have their origin at the margin of the 
valves, and w'hich terminate before the areal strife make their appearance. 
In some cases the area is surrounded by a concentric row of approxi- 
mating beads or dots or of abbreviated lines ; these collectively constitute 
the circlet. 
New Genus of Fossil Diatoms.* — Under the name Bergonia, M. J. 
Tempere describes a new genus of fossil diatoms from Barbadoes allied 
to Asterolampra and Bylandsia, but distinguished by its general aspect, 
and by the presence in its median region of two small oblong “ oculi.” 
13 . Schizomyeetes. 
Structure of Bacteria-! — Prof. E. Zettnow corroborates the view's 
of Klebs and Biitschli on the structure of bacteria. These authors 
regard the individual bacterium in the light of a cell, the chromatic 
portion, viz. that which is usually seen after staining with the ordinary 
pigments, being the nucleus and the sheath and its prolongations only 
seen with difficulty or after special preparation, as the plasma. The 
latter is usually extremely delicate, and its achromatism requires to be 
neutralized by means of mordants, and even then is not rendered evident 
with the same distinctness as the plasma. The illustrations given by 
the author are however clear enough, and these were obtained by photo- 
graphing the preparations made by Loeffler’s method. The micro- 
* Le Diatomiste, i. (1891) p. 70 (2 figs.). 
t Centralbl. f. Bakteriol. u. Parasitenk., x. (1891) pp. 689-94 (1 pi.). 
