286 THE ZOOLOGIST. 



worse unless prompt and energetic action be taken. On various English 

 rivers scarcity has led by gradual degrees to the extinction of the SalmonidcB ; 

 the Thames is a notable instance in point, and there are streams on the east 

 coast of Kngland, where Salmon once were numerous, in which nowadays 

 the king of fresh-water fishes is never seen. I am far from suggesting that 

 such misfortune is in store for the Welsh Dee, but the river is in an 

 unsatisfactory condition, and has been for some years. Among the causes 

 which are contributing to its decline the presence of Pike in large numbers, 

 both in the main river and its tributaries, is not the least injurious; these 

 predatory fish destroy enormous quantities of Salmon fry, and are equally 

 harmful to the Trout-fishing. During the spawning season gangs of men 

 raid the tributary streams by night, and it is manifestly impossible for one 

 or two watchers to cope with these lawless intruders. Apart from these 

 causes it is difficult to account for the deterioration of the Dee. It is not 

 seriously polluted. The Fishery Board has been at considerable pains to 

 improve it by putting up fish passes and a Salmon hatchery, and one can 

 only conjecture that over-netting in past years is responsible for the present 

 scarcity. The conservators would perhaps be well-advised to raise the charge 

 for net licences ; by seeking the co-operation of the riparian owners they 

 might still make adequate provision for watching the river." 



In the ' Transactions ' of the South African Philosophical Society 

 (vol. x. part '2) appears a very welcome " Bibliography of Books, Pamphlets, 

 Maps, Magazine Articles, &c, relating to South Africa, with special reference 

 to Geography. From the time of Vasco da Gama to the formation of the 

 British South Africa Company in 1888." The compilation is by Mr. 

 H. C. Schunke Hollway, and comprises 2099 separate entries. Although 

 zoological publications have not been made a specialty in the compilation, 

 the zoologist who wishes to read the observations of early travellers will find 

 this bibliography a guide to much neglected and little-known literature on 

 the subject. The zoologist will, however, find in the same publication 

 vol. x. part 3) a " Resume of recent scientific publications bearing on 

 South Africa from January 1st, 1897, to June 30th, 1898," which we hope 

 will be continued. 



The Tres Marias Islands are situated off the west coast of Mexico, 

 about sixty-five miles west from the port of San Bias. Their natural 

 history had been very moderately detailed. Grayson, a naturalist, made 

 three trips to the islands in 1865, 1866, and 1867, and, in conjunction 

 with Laurence and Bryant, published several papers thereon. Forrer 

 collected there for the British Museum in 1881, but no detailed account of 



