50 Coombe and Stiles: Diatoms at Hatfield West Moor. 
photomicrographs I have taken from other gatherings showing 
the emerging and intermingling of the protoplasmic contents of 
process), and (3) the frequent occurrence of long crooked 
frustules of Synedra, evidently newly born and requiring a series 
of sub-divisions to enable them to regain the symmetry of the 
parent frustule. (NOTE. Pda. and repeated examinations 
of several so-called ‘varieties’ of species among the Diatoms 
have convinced me that in the plastic condition in which the 
megafrustules emerge from the valves of the parent frustules 
they are liable to become silicified in a mis-shapen condition and. 
that, while undergoing the subsequent subdivision necessary 
to bring about the symmetrical form of the parent, they are 
frequently mistaken for new varieties.) 
I may mention that one of the West Moor gatherings con- 
tained some interesting specimens of the well-known alga 
Zygnema, in conjugation, and that among the Desmids which 
were mixed with the Diatoms I came across Closterium strto- 
latum, C. lunula, C. setaceum Ehrb., Euastrum oblongum and 
Staurastrum dejectum, the first named being the most common. 
Mr. Stiles also noticed Closterium ros/ratum and Cosmartum 
pyramidatum. 
The following is a list of the Diatoms found in the neigh- 
bourhood of West Moor, Doncaster, by Messrs. J. N. Coombe 
and M. H. Stiles :— 
Amphora ovalis Kutz. (R.). Navicula limosa Kutz. (F.). 
ree ra ovalis var. pediculus Navicula limosa var. acuta (F.). 
<)s Navicula exilis Grun. (C.). 
beecae lanceolata Ehr. (F.). Navicula iridis Ehr, (R.). 
Cymbella gastroides Kutz. (R.). Navicula peregrina Kutz. (R.) 
Cymbella cistula Hempr. (F.). Navicula Serians Breb. (R.) 
Cymbella cuspidata var. naviculi- Navicula humilis Donk. (C.) 
rmis Auersw. (R.). Navicula reinhardtii Grun. (C.). 
Encyonema ccespitosum Kutz. (R.). Navicula latiuscula Kutz. (?). 
Stauroneis phoenicenteron Ehr. (F.). Amphipleura pellucida Kutz. (F.). 
Stauroneis gracilis Eh * Pleurosig tenuatum W.Sm.(F.) 
Stauroneis anceps Ehr. (R.). Pleurosigma spencerii W.Sm. (F.) 
Navicula viridis Kutz. (F.) Gomphonema acuminatum Ehr. (F.). 
Navicula major Kutz. (R.) Gomphonema constrictum Ehr. (F.) 
Navicula oblonga Kutz. (F.) Gomphonema intricatum ae (F.). 
Navicula amphisboena Bory (R.). Rhoicosphenia curvata Grun. (F.). 
vavicula cuspidata Kutz. (R.). Achnanthes exilis Kutz 2, 
Navicula semen Eh Cocconeis placentula Ehr. (F.) 
Navicula elliptica Kutz. (R. ys Cocconeis pediculus Ehr. (F.). 
Navicula radiosa Kutz. (C.). Epithemia turgida Kutz. (R. -)e 
‘Naturalist, 
- ac sites 
ah elt 
—, el 
