ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
155 
longing to a new genus of Myxomycetes, which he names Amylotrogus. 
It attacks also the starch of wheat, and several distinct species are 
described. Some of these species develop their plasmodes superficially, 
others within the starch-grains; in the former case, they frequently 
branch and anastomose. The plasmodes can retain their vitality for a 
long period in a desiccated condition. They have a discoid form and a 
pale violet-red colour. Two species are specially described, A. ramulosus 
and discoicleus. 
Cytidium, a new Genus of Myxomycetes.* — In a list of Myxomy- 
cetes from the Miami Valley, Ohio, Mr. A. P. Morgan describes the new 
genus Cytidium , with the following diagnosis : — Sporange globose or 
rarely ellipsoidal, stipitate ; wall a thin membrane, with an external 
layer of minute granules of lime, ruptured irregularly. Stipe more or 
less elongated, tapering upwards, and entering the sporange as acolumel. 
Capillitium of slender tubules, arising from the columel, repeatedly 
branching and anastomosing to form a regular network, the extremities 
attached on all sides to the wall of the sporange, the tubules containing 
at intervals nodules of lime. Spores globose, violaceous. Near Phy- 
sarum, but distinguished by the columel, which gives origin to the 
capillitium. 
Protopliyta. 
a. Schizophyceae. 
Reproduction of Marine Diatoms. f — Mr. G. Murray describes a re- 
markable mode of propagation observed in certain pelagic diatoms chiefly 
belonging to the genera Bidduljpliia , Coscinodiscus , and Clisetoceros. In 
Biddulpbia mobiliensis “cysts” were observed within the parent-cell, 
with only slightly silicified wall, and without the characteristic spines. 
They appear to have the power of dividing and multiplying before 
assuming the characteristic parent-form. A similar phenomenon was 
observed in Coscinodiscus concinnus, but here the protoplasm divides before 
the production of the “ cysts,” two of which were found within the same 
parent-frustule, differing from one another in form, and in the width of 
the girdle-zone. It is not uncommon to find the young Coscinodisci in 
“ packets ” of eight or sixteen, resulting apparently from further binary 
division within the frustules, which are found accompanying them in an 
empty state. These young forms have their membranes either very 
slightly silicified or not at all, and are, therefore, capable of increasing in 
size. A similar formation of “ packets ” of eight or sixteen young indi- 
diduals within the parent-frustule was observed in several species of 
Clisetoceros. 
Diatomaceous Earth.J — Mr. T. W. E. David gives particulars of the 
position and composition of the diatomaceous earth found in various 
localities in N.S. Wales. He states that they are always found in 
association with volcanic rocks, probably in consequence of the large 
amount of silica contained in solution in the hot springs. One of the 
most important deposits, that of the Warrumbungle Mountains, is asso- 
ciated with trachytic lavas and tuffs of early Tertiary, possibly of late 
Cretaceous Age. 
* Journ. Cincinnati Soc. Nat. Hist., xix. (1896) pp. 1-44 (3 pis.). 
t Proc. Roy. Soc. Edinburgh, xxi. (1896) pp. 207-19 (3 pis.). Cf. this Journal, 
1896, p. 704. X Proc. Linn. Soc. N.S. Wales, xxi. (1896) pp. 261-8 (2 pis.). 
