G. GENERAL NATURAL HISTORY AND ZOOLOGY. 309 



pass down a tube so as to enter the next tank at the bottom, 

 causing a continued displacement of the water already in 

 the tank. The reservoir, which occupies the space under 

 the large liall, is divided into nine compartments, so that 

 in case of accident to any part, it can be cleared of the 

 water and repaired while the other sections remain in op- 

 eration. 



The total capacity of the reservoir is 600,000 gallons, and 

 the total amount of water in the reservoir and tanks together 

 will be 750,000 gallons. For the circulation eight rotary vul- 

 canite pumps are erected, which are capable of sending 56,000 

 gallons through the tanks in an hour if needed, though it is 

 calculated that 15,000 to 20,000 gallons will be the average 

 amount. The salmon will have a fifty-feet run. All the 

 pipes, culverts, etc., are of vulcanite, but the glass fronts of 

 the tanks are fitted in cork. January 27, 1875, 255. 



DECREASE OF BIRDS liST MASSACHUSETTS. 



There are, says Mr. J. A. Allen, few data obtainable rela- 

 tive to the subject of the extinction of our birds. The num- 

 ber of indigenous species belonging to the fauna of the state 

 is about 310. Of these, two, the Great Auk {Alca impennis) 

 and the Wild Turkey, have become wholly extirpated, and 

 two others (the Pinnated Grouse, Ciqndotiia ciipido^ and the 

 American Swan, Cygmis americaniis) are so nearly so that 

 the former is found at only one or two limited localities, and 

 the latter is but a chance visitor. The Brown or Sand-hill 

 Crane (Grus canadensis)^ and perhaps a second (the White 

 or Whooping Crane {Gnis americamis), were formerly inhab- 

 itants of the state, though extirpated at so early a date that 

 they have not as yet been recognized as belonging to its 

 fauna. Among those which have greatly decreased in num- 

 bers are the Red-winged Blackbird (Agelcmis 2yhoemceus), the 

 Purple Grackle {Qmscalus purpur-eus), the Crow (Corviis 

 americaniis)^ the Raven (Corvus corax), the Pileated Wood- 

 pecker {Hylotomus 7:)^7ea/^<s), the Red-headed Woodpecker 

 {3felanerpes erythrocephalus)^ the Wild Pigeon {Ectopistes 

 migratorius)^ and the Snow Goose {Anser hyperhoreus). To 

 these, says Mr. Allen, might be added, as among those which 

 have also notably decreased, most of the wading and swim- 

 ming birds, and nearly all of the rapacious species. None of 



