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to which has been given the name of Cysticercus lumhriculi. 
The seat of this parasite is the general cavity of the host’s 
body, between the intestine and the integument, along all 
the segments. There is generally but one of these parasites, 
hut in exceptional instances several may exist in one host. 
As many as eight have been found by Dr. Ratzel in one 
Lumbriculus. The body of Cysticercus lumhriculi is round, 
and of an average diameter of 0 - 42 mm. Its outer membrane 
consists of a vesicle, the .tissue of which is made up of soft 
cells, with no external membrane, and containing granular 
nuclei. Among these cells are scattered a few fat- globules 
and some muscular fibres. Within this is a second mem- 
brane, which is a resisting chitinous capsule, perforated at 
the upper and lower parts by two openings. Near these 
openings the wall of the capsule is thickened, and at the 
lower one there is a tending inwards of the external vesi- 
cle, and a union of this with the margins of the internal 
chitinous capsule. At this point the head of the parasite is 
developed, and subsequently a short wide neck, in which are 
disposed numerous calcareous bodies. The head carries a 
rostellum, a circlet of ten hooks, and at an advanced stage 
sucking discs. Between the external vesicle and the internal 
chitinous one is an interspace which is filled with a transpa- 
rent fluid. 
Dr. Ratzel thinks it very probable that this Cysticercus 
may become developed into a Taenia, infesting birds, and 
particularly birds which frequent marshes, as it has been 
found only in Lumhriculi which live in marshy places, and 
never in those taken from flowing water and localities not of 
a marshy character. 
On the Reproductive State of Saprolegnia monoica is the 
title of a paper by Johannes Reinke, in Schultze’s Archiv, v. 
Part 2. 
Microphytology. — Notes on Diatomacere from Danish Green- 
land, collected by Mr. Robert Brown. By Professor Dickie, 
Botanical Society of Edinburgh. No. I. — All the species 
recorded were British, with the single exception of Hyalo- 
discus subtilis, originally described by the late Professor 
Bailey, from Halifax; found also on the shores of North- 
West America, and now on the shores of Greenland. 
On the Diatomaceous Frustule. By John Denis Mac- 
donald, F.R.S. Annals and Mag. Nat. History, Jan., 1869. — 
Dr. Macdonald observes that Dr. Wallich was the first to 
put forward a part of the views which he expresses in this 
paper, and to show that the “ membrane ” between the two 
valves consists of a hoop enclosing a second hoop, so that one 
