223 



1162. The dried head of the Puffin (Fratercula arctica). 



Prenatal by If. Bdloct, E*q 



1 163. The dried head of a young Puffin (Frattrcula arctica). J/mttfrian. 



Family Colymbida. 



Genus Uria*. 



1164. The skeleton of the Guillemot (Una Troile). 



There are 2 1 vertebrae between the skull and sternum, to the last rix of whirh are attached 

 ribs, articulated to the rtemum by bony hrmaiiophyses. Anterior to these then is one pair 

 of rib*, free, and unattached to the sternum : the laat or eighth pair of rib* is attached to the 

 Mcrum and to the sternum by long haemapophyses. There are 8 caudal vertebrae. 



The donal vertebrae are bound togrther by many ossified tendon* of the deep-seated spinal 

 anoaciM. The rib* are remarkable I'or the progressive elongation of their baeniapophysca, and 

 the acute angle* at which they articulate with the pleurapopbyse*. 



J/wr. Sou th. 



Genus Colymbtu. 



1 165. The skeleton of the Great Diver (Colymbas glaciali*). 



The niperorbital glandular foasae are unusually long, and divided only by a thin ridge above 

 the orbits; the temporal depressions, likewise, are divided by a parietal crixta, and by a 

 stronger fuperoccipital crest from the occipital depressions, which are divided from each 

 other by a sharp median occipital ridge. The mastoid is convex above the tympanic articu- 

 lation, a* if prvwed up by it. The common base of the procuemial and cctocurraial ridg^n 

 extends upwards in the direction of tlie shaft of the tibia nearly two inches beyond the femo- 

 ral artir ulation. There are 21 vertebra; between the skull and sacrum, and the la*t six sup- 

 port riba, which are articulated by their haetnapophyses to the sternum. The seventh and 

 eighth pain of moveable ribs are attached to the sacrum, and are articulated to the sUrnum 

 by hsemapophyes : the first rib is free and unattached to the sternum. There are 7 caudal 

 vertebrae. Hypapophyses are developed from the but three cervical vertebrae, the seven dor- 

 sal vertebrae and the first sacral vertebra ; most of them are remarkable for their great length 

 and terminal bifurcation. 



Mm. Son tli. 



1166. The pelvis and bones of the right leg of the Red-throated Diver 



trionalu). 



No Puffin* or Guillemot* arc known to exist south of the Equator. 



