TRANSACTIONS OF SECTION D. — DEPT. ZOOLOGY AND BOTANY. 589 



The following Reports and Tapers were read : — 



1. Second lieport of the Committee for the Investigation of the Natural 

 Historij of TimoT'laut. — See Reports, p. 275. 



2. Report of the Committee for the Investigation of the Natural History of 

 Socotra and the adjacent Highlands of Arabia and Somali Land. — See 

 Reports, p. 281. 



3. Report on the Record of Zoological Literature. 



4. On the Broiun Colouration of the Southampton Water. By A. Angell, 



Ph.D., F.C.S. 



The author showed that the peculiar colour of the Southampton estuarine water, 

 which turns to a rusty hrown tint in the summer of each 3-ear, is due solely to the 

 presence of a small ciliated orgauism, Peredinium fuscum, which is classified by the 

 best authorities amongst the ciliated protozoa, or microscopic animals. This posi- 

 tion is generally accepted, but the author, seeing that they evolve oxygen, contain 

 chlorophyl (plant colour-matter), have no mouth or opening of any kind, never con- 

 tain foreign bodies, have cellulose walls, and, after death, give off an odoiu- of 

 decaying sea-weed, is of opinion that they are more plants than animals. He 

 fiyther sought to show that their presence is due to the large amount of sewage 

 thrown into the river at and about Southampton. The seaward margin of the 

 river water is distinctly mapped out by the brown colour, and the autlior noticed 

 that this never leaves the estuarine basin, and pointed out that a measurement of 

 the oscillations of this line provides a true index of the tidal motions, and shows 

 that tlie water in the river is but very slowly, if at all, changed by the rise and fall 

 of the tides. He showed it was an error to suppose that in tidal rivers and land- 

 locked estuaries a fresh supply of water is given at every tide, and that, as a matter 

 of fact, the time needed in which a single change in such waters as Southampton 

 water will take place is dependent more upon the small flow of fresh water and 

 surface evaporation than upon tidal influences. It is not, therefore, safe to pollute 

 tidal waters with sewage; the impression that the filth goes out to sea with the 

 tide is utterly false. Our peculiar brown colour gives us an indication bv which we 

 can learn that practically a change of the water of the Southampton Water, and 

 therefore of all other similarly situated tidal river-mouths and land-locked estuarine 

 basins, is but very slowly, if ever, effected by the tides. Enough filth, he said, is 

 poured into the river to make it in hot weather a stinking abomination ; but, in 

 accordance with nature's provisions against such unnatural proceedings, a vast army 

 of minute organisms is set to work, and the water is kept tolerably sweet. If it can 

 be shown 1 hat this creature, whicli is barely visible to the naked eye, performs 

 the chief function of plants — liberates oxygen— and is at the same time an animal 

 and therefore carries on direct nitrification, it is indeed most wonderfullj' adapted, 

 by tliis double set of powers, to keep our sewage-polluted waters as sweet as is 

 possible. Notwithstanding the unsightly colour of Peridinium fmcum, we cannot 

 afford to do without it in our river. When the day comes that the authorities of 

 Southampton see fit to keep out the sewa<re now flowing into its waters so as to 

 free thi'm from such pollution, the Peridinium fuscum, no longer needed in such 

 vast quantities, will retire into its normal position — become less obtrusive, and leave 

 the water a pure translucent green.. 



5. On the Distribution and Dates of Spring Migrants in Yorkshire, compared 

 toith West of England and Ireland. By T, Lister. 



Not including very rare species which occasionally reach Britain, we may say 

 of the Syhiidip, Yorkshire is visited by all except the locally-distributed species 



