OVARIES IN CERTAIN DRITISII BIRDS. 79 



EXPLANATION OP THE PLATES. 



For fuitlior details see Appendix (p. 7i). 



Plate IL 



Paired Ovaries, 



Fi};s. 2''-14". Sparrow-IIawk (AccipUer nisus). 

 l''-8''. Kestrel {Falco tinimnculus). 



(r., right ovary. I., left ovary.) 



Plate III. 



Paired Ovaries. 



Figs. 1' 5^ Ilcn Harrier {Circus cyaneus). 



r'. Miirsh Harrier (C /srM.</mo«e«s). 



V-Z\ Montagu's Harrier (C. ciiieraceus). 



V. Hohhy (Falco subhiiteo). 



1*. Peregrine Falcon (Falco peregrinus). 



1'', 2''. Great Crested Gi-ebe (Podicipes crista tus). 



l'-3\ Red Grouse (Lagopus scoticus), 



1''. Black Grouse (Tetrao tetrix). 



1'. IJewick's Swan (Ct/c/nus betuicki). 



1'", 2"'. Water Kail (Eallus aquaticus). 



1". Woodcock (Scolopax rasticula). 



1 ", 2". Little Gull (Larus ininutus). 



(r., right ovary. I., left ovary). 



Plate IV, 



Paired Ovaries. 



Fig. 1. Sjiarrow-Havvk (Accipiter nisiis) X 1|. Both ovaries present, the right 

 nearly exhausted and containing small eggs only. Both oviducts well 

 developed ; the right three or four times the size of the left and ajjparentlj- 

 the last in use; the left oviduct is well defined, the ovarian end of the 

 duct is turned directly downwards and to the left, and the Ostium abdo- 

 minale is clearly seen, (Appendix 14".) 



2, Hen Harrier (Circus ci/aneus) Xlj. Symmetrical paired ovaries equally 



developed and containing eggs of approximately the same size. 

 (Appendix 5'.) 



3, Great Crested Grebe (Podicipes cristatus) Xlf. Asymmetrical paired 



ovaries. The right ovary lies below the left, and is mostly in the left half 

 of the body-cavity. (Appendix 2''.) 



Plate V. 



Microscopic sections of the ovaries of the Hen Harrier (Circus cyaneus). 

 (Appendix 6'). 



Fig. 1. Left ovary X4| showing general ovarian structure. 



2. A selected ovum from fig. 1 showing germinal spot, proto])lasm, germinal 



epithelium, and vascular connective tissue capsule (XO'J). 



3. Right ovary X5, 



4. A selected ovum from fig. 3 X50. 



