338 SECTIONAL TRANSACTIONS.— D, E. 



Dr. J. N. Oldham. — Helminths as biological controls of pests. 



Dr. B. G. Peters. — The scope and aims of the Bureau of Agricultural 

 Parasitology. 



Afternoon. 

 Dr. Michael Grabham. — Subtropical ichthyology. 



Miss R. C. B AMBER (Mrs. Bisbee). — The impurity of the Mendelian 

 Recessive. 



Mr. W. C. Miller. — A sheep-goat hybrid. 



Prof. C. J. Patten. — The mystery of bird-migration. 



Opportunities of making repeated observations at Irish Light-stations 

 have convinced me that migrating birds endeavour to find their viray by 

 reacting to their environment, and often profiting by experience in varying 

 degrees according to the exigencies of the situation. Birds possess an 

 ' eye-brain ' ; their sense of vision is extraordinarily acute and by no 

 means indiscriminating. It seems unreasonable to brush aside the idea 

 that migrants may obtain guidance by taking stock of landmarks. Further- 

 more, the sense of hearing can play a part. The wash of the waves is 

 a reminder to hug the coast — the guide-line of primary importance. The 

 courses of great rivers are followed by overland migrants. It is noteworthy 

 that most remarkable fraternities are often formed en route, thereby affording 

 inexperienced juveniles the opportunities of being piloted by adults who 

 have been over the ground. In thick weather migrating birds often go 

 astray, and, arriving at unaccustomed haunts, are classified as rare and 

 accidental vagrants. When the gloom deepens the voyagers become sorely 

 handicapped, while a dense and prolonged fog will put the brake effectually 

 on migration. It is surmised that birds may be endowed with a special sense 

 of direction — an unconscious, unerring instinct. Herein lies the mystery 

 of migration which furnishes an inadequate and illogical hypothesis, which 

 field observations carried to a further degree will tend to dispel. 



SECTION E.— GEOGRAPHY. 



Thursday, September 1. 



Presidential Address by Prof. H. J. Fleure on The geographical study 

 of Society and World Problems. (See p. 103.) 



Prof. P. F. Kendall. — The physical setting of York. 



York is not the capital of the three Ridings of Yorkshire, but constitutes 

 a division of its own as the seat of the Archbishopric. Its geological posi- 

 tion is similarly detached, standing upon the lowest rocks of the Secondary 

 series, the Triassic sandstones, into which many wells penetrate. 



The three Ridings do not correspond exactly with the geological structure 

 — the North Riding embraces not only the area of Archean, Ordovician, and 

 Silurian rocks and Lower Carboniferous rocks of the west, but also includes 

 an inlier of Coal Measures and Permian at Ingleton and the belt of Magnesiari 



