232 Shufeldt, Eggs of Reptiles and Birds Compared. [ 



Emu 

 St April 



passing down the oviduct (either butt or apex first) may some- 

 times be at rest ; sometimes — either slowly or rapidly — advance 

 without rotation, or various rotary movements may be imparted 

 to it through the peristaltic and anti-peristaltic contractions of 

 the walls of the oviduct — the pigmentary glands being functionally 

 active all the time in those cases where pigment is being deposited. 

 Within the past year or so I have published a number of 

 illustrated articles on oology, including eggs laid by birds of this 

 country as well as others from Australia and other parts of the 

 world. Some of these papers have appeared in The Emu, The 

 Condor, The Blue-Bird, and elsewhere.* As a matter of fact, 

 a great many monographic and other works, some of which are 

 superbly illustrated with hundreds of coloured figures, have 

 already been devoted to this science by oologists in many parts 

 of the world. Still, there remains a vast store of facts, together 

 with undescribed specimens of eggs, to be added to the present 

 literature of the subject, which will require the labours of many 

 naturalists, extending over many years to come, to work up into 

 monographs, articles, and other contributions. 



Explanation of Plates. 



(Figures all natural size, and reproductions of the author's photo- 

 graphs, made by him direct from the specimens.) 



Plate XXXVII. 



Fig. 1. — Fossil egg of a bird of an ellipsoidal form. Collected at 

 St. Gerand de Puy, France, and presented to the United 

 States National Museum by Dr. R. W. Shufeldt. Oligocene. 

 No. 6,496. Viewed upon lateral aspect, and exhibiting in 

 places both shell and concution. 



Fig. 2. — An egg of Strix v. varia, remarkable for its nearly perfect 

 sphericity. This specimen was collected by Mr. Edward J. 

 Court, of Washington, D.C., and was for some time in his 

 collection. Subsequently Mr. Court presented it to Mr. 

 A. B. Howell, of Covina, California. 



Fig. 3. — Lateral view of the white, ellipsoidal egg of a 3,legapode 

 [Catheturus purpureiturus). Collection of Edward J. Court, 

 of Washington, D.C. In form and some other respects this 

 egg resembles more or less closely the egg of certain 

 Crocodilia among the RepHlia. 



Plate XXXVIII. 



Figs. 4-9. — White, ellipsoidal eggs of North American Humming- 



Birds of different species. 4, Ruby-throated Humming-Bird 



(Archilochus colubris) ; 5, Black-chinned Humming-Bird 



{A. alexandri) ] 6, Costa's Humming-Bird {Calypie costcp) \ 



7, Broad-tailed Humming-Bird (Selasphorus platycercits) ; 



8, Allen's Humming-Bird (5. alleni) ; and 9, the CaUiope 

 Humming-Bird {Stellula calliope). Collection of E. J. Court. 



♦Shufeldt. R. W.. "Comparative Oology of North American Birds," 

 Report of the U.S. National Museum for 1892, pp. 416-493. 



