Oh. XX] 



ARCH.EOPTERYX OF SOLENHOFEN. 



397 



type." In the young ostrich from eighteen to twenty caudal vertebra; 

 may be counted, seven or eight of which are annexed to the sacrum, 



¥iff. 890. 



Tail of Arcluxopfpryx macrura, Owen, and Feather of A. UthograpJiia, Meyer, from the slate 

 of Solenhofen ; and tail of living bird for comparison. 



A. Series of caudal vertebrae (with impressions of the tail-feathers preserved in situ) of Ar- 

 <■ chceopteryx macrura, Owen, § nat. size. Drawn from the specimen in the British 



Museum (ventral aspect). 



B. Two of the caudal vertebra?, nat. size, showing their shape and the absence of transverse 



processes. 



C. Single feather, called Archmopteryx Mthograpliica by Yon Meyer. Natural size. 



This feather, upon which the genus was established in 18G1, was discovered at Solen- 

 hofen. See " Jahrbuch fur Mineralogie, 1 ' 1S61, p. 561. 



D. Tail of recent vulture {Gyps Bengalensis), showing the points of attachment for the prin- 



cipal tail-feathers (dorsal view, J nat. size). 



E. Profile of caudal vertebrae of same, to show the broad terminal joint, or "ploughshare" 



bone,/, of the tail, the same as that seen foreshortened at/D, so largely developed in 

 nearly all living birds. £ nat. size. 



N. B. — The figures 1 to 6 indicate the correspondence between the vertebra? in the two 

 views D and E. 



/E and/D indicate the position of the terminal joint. 



The dotted lines E, e, e, show the direction of the quill feathers of the tail when seen 

 in profile. 



The ploughshare bone can be elevated at pleasure (as seen at / E), to meet the ex- 

 tended beak of the bird when seeking the coccigian oil-gland (which is placed upon this 

 terminal joint) to lubricate its feathers while preening. Only the "primaries" or great 

 tail feathers are represented in fig. D ; the bases of these and the rest of the vertebra? 

 are clothed in secondary feathen and down. 



while two or three are welded together to form the slender terminal 

 bone, which in this and other running birds (cursores) is not plough- 

 share-shaped. 



It has been already stated that no species of British fossil, whether 

 of the vertebrata or invertebrata, are common to the Oolite and Chalk, 

 or, to speak more strictly, are common to the marine beds of these 

 two groups which stand nearest to each other, namely, the Portland 

 limestone aiid the Atherfield beds ; but while there is this great break 



