ALCIDiE. 193 



posterior bonier of the distal extremity. The contour of 

 this specimen accords very closely with that of Colymbus 

 (compare Milne-Edwards, ' Oiseaux Fossiles de la France,' 

 pi. xlviii. figs. 4-5), exhibiting the same curvature of the 

 head, with a long articular surface for the furcula, the 

 same great expansion of the distal extremity, on which 

 the broken surface for the attachment of the process on 

 the posterior border is distinctly visible. The surface 

 for articulation is of the narrow form, with the large up- 

 ward extension on the inner aspect of the bone character- 

 istic of the family. Hastings Collection. Puixhased, ISoo. 



Fi- 43. 



Colymboidcs cdujUcus. — Ventral aspect of the left coraeoid ; from the Upper 

 Eoceue of ITordwcll. \. Letters as in fig. 23 (p. 84). 



30330. The imperfect anterior portion of a sternum probably refer- 

 able to this species ; from HordwcU. The left coracoidal 

 groove fits the preceding specimen. In the presence of a 

 deep concavity in the middle line between the coracoidal 

 grooves, the inner surface of this specimen agrees with the 

 sternum of Cohjmhus, to which it approximates in the 

 slight development of the episternal process. 



Hastings Collection. 



Family ALCID.E. 



The tarso-mctatarsus is not compressed laterally, and has a 

 slightly developed talon, usually with three open grooves, but the 

 innermost of which may form a closed tube {Alca tarda). The 

 cncmial crest of the tibia extends only a short distance above the 



o 



