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FORMATION OF A LINCOLNSHIRE NATURALISTS’ UNION. 259 
in our power in promoting the furtherance of the natural history 
activities of the county of Lincoln, that we were induced to leave the 
Yorkshire side of the ‘muddy’ Humber, and to attend the meeting of 
Lincolnshire naturalists at Mablethorpe. The time at our disposal 
was short, for we only reached Mablethorpe about 11 a.m., and, by the 
time we had arrived at Saltfleetby, the place at which operations 
practically commenced, it was nearly noon. 
Taking a rough bird’s-eye view, the district presented a striking 
resemblance to many parts of Holderness, a flat-lying country, with 
numerous dykes and drains intersecting each other. Such at any 
rate, were the distinguishing features of our route between Saltfleetby 
Station and the sand-dunes of the coast. It was, however, soon 
made plain that the drainage system of the district was not designed 
to serve agricultural interests to such an extent as appears to be the 
case in Holderness. The frequent cleansing of the drains seriously 
interferes with the development of the mollusca inhabiting them. 
At Saltfleetby there were manifest indications of the dykes having 
been left undisturbed for some time past, which had favoured the 
growth of Physa fontinalis to the average length of half-an-inch, and 
to an unusual development of that elegantly formed shell Bythinia 
leachit, which in some few instances had been such as almost to 
rival in size its clumsy-looking relative, B. tentaculata. Both species 
were exceedingly abundant; in fact, the pectinibranchiate mollusca 
Were uncommonly well represented in the dykes of the route. 
A short distance from the coast we halted by the bank-side of a wide 
_ drain which had an average depth of about eighteen inches of water, 
a light sandy bottom, and contained very little vegetation. It was 
not difficult soon to distinguish grovelling at the bottom, the heavy 
0 
— form of Viviparus contectus. On the other side of the road one 
more gill-breathing mollusc occurred plentifully on a species of 
L£nteromorpha which covers the surface of the water. | ieee = 
a3 Vateata cristata. 
3 vegetation ; in places the surface was 
_ the less generally distributed Z. gibda, and here and there the unmis- . 
With the exception of the focaliiy. where Vines was takes : 
here was, everywhere over the route, a luxuriant growth of ne 
takeable reniform-shaped leaves of the frogbit (Hydrocharis morsus- 
vane). The uppermost whorls of the shell of Limnea stagnalis 
__ Were occasionally to be observed as the animal would be struggling — 
oa the mass of weeds from which it seemed to be endeavouring to” : 
7 means oe abet of this ——— — 
Sept. 1893, 1893. 
