28 HULL SCIENTIFIC AND FIELD NATURALISTS CLUB. 



itself into a ball when alarmed. P. varians is more abundant 

 after spring tides, but C. longicorne lives in tubes in the mud 

 until the pools dry up; I have found them in mid-winter. In 

 1902, shoals of Neomysis vulgaris were to be found in all the 

 Humber pools from Saltend to Spurn and in most of the 

 brackish drains where I had not taken it previously. Paludes- 

 trina ventrosa, which occurs in all our brackish ditches inland, 

 is abundant on the Ulva in the Saltend pools, with some 

 P. stagnalis, and small whitish specimens of the latter are 

 found on the stones on the foreshore, but this species 

 evidently does not nourish here. Another interesting mollusc, 

 Alexia myosolis, lives amongst the grass just below high 

 water mark of average tides, especially along Hedon Haven. 

 Under the stones in front of Paull, and at the foot of the 

 piles which protect Saltend Common, we find the isopoda, 

 Ligia oceanica, Jcera nordmanni, and Ido/ea marina, and the 

 amphipoda, Gammarus marinus, G. locusia, and Orcheslia 

 littorea. The larger specimens of Ligia may often be seen 

 on the timber basking in the sun, but their exceptional 

 agility renders them by no means easy of capture. Worms 

 are represented by Nereis pelagica and X. divers/color, and 

 mollusca by the periwinkle, Littorina radix. In front of 

 Paull, Membranipora monostachys decorates bricks and broken 

 tiles from half-tide level downwards, and it is fairly abundant 

 also on the stones at Saltend, though these are barely sub- 

 merged at neap tides. A red alga, Rhodochorton rolliii, 

 previously found by Mr. J. F. Robinson at Hull, forms a 

 velvet coating on these stones, and Porphyra vulgaris grows 

 amongst Enteromorpha compressa on the timber. 



All these are common along the Humber foreshore in 

 similar localities, and if the narrow belt of chalk which 

 suffices in such situations formed an adequate protection 

 elsewhere, we should meet with little else until we reached 

 the " clays " of Kilnsea and Spurn ; but owing to the change 

 in the direction of the Humber currents, or the narrowing of 

 the channel, it usually happens that the reclaimed areas 

 require much stronger safeguards against erosion shortly after 

 enclosure, and these generally consist of banks of chalk at 

 right angles to the river bank. If these " cranches " run 

 out into deep water, they provide a Laminarian zone, desti- 

 tute, of course, of Laminaria, but affording a suitable 

 habitation for many unexpected species. 



The most notable of these cranches is Well Creek, about 

 three miles east of Paull, and fifteen miles in a direct line from 

 Spurn. It is commonly known by this name amongst Hull 



