LABORATORY WORK, XX 365 



2. Number of tail feathers ? 



3. Number of primaries ? 



4. How many segments in the leg ; in the wing ? 



TOPICS FOR FURTHER STUDY 



1. The introduction of the " English " sparrow into America and 

 similar instances of introduction and spread of exotic species. 2. The 

 food and habits of the " English " sparrow in America. 3. The 

 native sparrows. 4. Other groups of birds : thrushes, bluebirds, tit- 

 mice, nuthatches, creepers, wrens, warblers, tan age rs, swallows, wax- 

 wings, vireos, shrikes, larks, orioles, crows, flycatchers ; parrots and 

 cockatoos; toucans and cuckoos, kingfishers ; woodpeckers, humming- 

 birds, swifts, goatsuckers ; pigeons ; grouse and fowl ; ostriches ; 

 waders ; swimmers, and divers. 5. The migrations of birds ; migra- 

 tion data. 6. Flight of birds. 7. The food and economic importance 

 of birds. 8. The preservation of birds. 9. Fossil birds. 



XX. MOUSE (Mus mustelus) 



Tame mice may be obtained from bird fanciers in most of our large 

 cities. 1 They can be kept in the laboratory indefinitely. Galvanized 

 wire cages with doors and galvanized iron bottoms are serviceable. 

 Supply with cotton, hay, or excelsior for a nest. Keep at an equa- 

 ble, moderate temperature, and pay great attention to cleanliness. 

 Feed on oats and bread, with occasional fruit, carrot, and cooked meat. 



DRAWINGS 



1. Side view (left). Name parts. Natural size. 



2. Head, dorsal view, x 1.5. 



3. Fore foot (left), dorsal surface, x 2. 



4. Fore foot (left), palmar surface, x 2. 



5. Hind foofr (left), dorsal surface, x 2. 



6. Side view of skull, x 3. 



7. Upper surface of lower jaw showing teeth, x 3. 



8. Incisor tooth (free), x 10. 



i Mr. H. C. Ostendorf , 420 N. Eutaw St., Baltimore, has been found reliable 

 by the writer, and keeps a stock on hand. 



