1891.] 



VARIATION OF THE LEPORINE STERNUM. 



161 



<^-^Q^ 



Series of sterna of Lepus cimiculus showing absorption of the seventh 

 sternebra (dorsal aspect). Nat. size. 



A, B, 0, D, E show the seventh sternebra ossified ; F, the seventh sternebra 

 only represented in cartilage (the two halves had not as yet completely 

 fused); G, normal sternum; H, side view of sternum, showing dorsal 

 displacement of the seventh sternebra ; I, sternum of embryo of 3 cm. 

 total length ; J, horizontal longitudinal section of sternum of embryo of 

 7 cm. total length ; K, longitudinal section of sternum of embryo of 11 

 cm. total length ; L, sternum of embryo of same age. 



Reference letters : /., fontanelle ; pe., ensiform process ; S. V-VIII, sternebrae. 



Proc. Zool. Soc— 1891, No. XI. 



11 



