THE MARINE FAUNA OF THE HUMBER DISTRICT. 35 



found in the narrow drain which runs for three miles at the 

 side of the road through the reclaimed area known as Cherry 

 Cob Sands. Neomysis vulgaris usually remains near the 

 clough amongst the spreading fronds of Ulva latissima ; the 

 others are common throughout the whole length. About 

 two-and-a-half miles from the outfall, the zoophyte, Gono- 

 t/ivnea loveni, occurs on Potamogeton and on the sides ot the 

 culverts, with a Membranipora whose identity was for a long 

 time doubtful. The latter was first found on Potamogeton, 

 forming a complete cylinder round the stem, and it similarly 

 encrusts Chcetomorpha and hawthorn branches which have 

 fallen into the drain, or spreads in radiating colonies over 

 bricks, but under the bridges it forms masses of superposed 

 plates, often an inch thick, extending along the wall in a 

 band two or three inches wide just below the water line. 

 Sometimes it assumes a more erect habit and forms a 

 cornucopia-shaped structure about an inch in height. The 

 masses of plates are very fragile, especially when the animal 

 is dead, and the larger growths will seldom bear removal. 

 One specimen, afoot in length, which I saw in August, 1902, 

 had been built round a branch an inch thick, which projected 

 from the mud ; the diameter had been trebled by the over- 

 lapping plates, and encrusted Cheetomorpha hung in white 

 festoons from the upper end. When normally encrusting 

 Potamogeton, &°c, the zocecia are arranged alternately in 

 straight or spiral lines, somewhat resembling M. mem- 

 branacea, and bear two erect spines at the upper end, but 

 they differ from that species in the less rectangular shape of 

 the cell and in the thickened cell wall which is milled or 

 granulated along the upper edge and finely denticulate on 

 the inner. Professor Harmer considers that this form should 

 be referred to M. lacroixii. 



The masses of plates, in which the zooecia are spineless 

 and without the inner denticulations, agree almost exactly 

 with M. monostachys, var. fossaria, recorded by Hincks from 

 similar localities in East Anglia, specimens of which were 

 kindly sent me by Professor Harmer. I have also found the 

 spineless form normally encrusting a brick in company with 

 the other, and where the two colonies met and produced free 

 expansions, one or two of the cells possessed six spines. ■ In 

 addition, two small upright tubular colonies, resembling 

 miniature corals, exhibit on some of the zocecia the single 

 spine of M. monostachys though more upright than in the 

 typical form. 



Specimens kept in a small brackish water aquarium lived 



