420 • SULA BASSANA. 



cannot presume to determine from few facts and small data. 

 The bird in question was caught on the Bass in May 1831, 

 and sent to me for description by Mr. Stables. 



Apparently adult, and having the general appearance of 

 the Common Gannet. Primaries 10, secondaries 2G, tail- 

 feathers 12. The principal differences are the following : — 



The bill is shorter, and at the base thicker. 



The space from the eye to the base of the bill is shorter. 



The black line of bare skin is extended down the neck to 

 more than half its length, w^hereas in the Common Gannet it 

 is only about 2 inches long. 



The secondary quills are dark purplish-brown ; white in 

 the Common, but still dark brown in its second year. 



The tail is dark brown ; white in the Common, but still 

 dark brown in its second year. 



Length 36 inches ; extent of wings G4 ; bill along the 

 ridge 3|, along the edge 5^ ; tarsus 2| ; middle toe 4^. 



In specimens from the Bass, the dimensions of the diges- 

 tive organs vary considerably, as in many other species of 

 birds. Thus : — 



In an adult male shot in May 1824, and of which the 

 length Avas 36, extent 70, bill 4, tarsus 2^, toe 4f ; the oeso- 

 phagus 15, intestine 60. 



An adult male, 23d August, 1836. — Length 37 inches, 

 extent 72; ocsopliagus 18; stomach If; intestine 64. 



An adult male, 8th July, 1837. — Oesophagus 15 ; intestine 

 60-1-, of which the rectum 4^ ; coeca 5-^5-. 



An adult female, 8th July, 1837.— ffisophogus 14; in- 

 testine 61-1-, of Avhich the rectum 4^; cceca -j*^. 



An adult, 20th July, 1824.— Length 33, extent 67, bill 

 4i, tarsus 25-, toe 41. 



A second year bird. — Length 35^, extent 70 ; bill 4^ ; 

 tarsus 2, middle toe 4^. 



The American birds which I have seen were mostly a 

 little larger. Three preserved in rum measured : — Length 

 38f , 38|, 37 ; extent 73, 72, 68^. Of one of them, oeso- 

 phagus 18i, stomach l^V ; intestine 58}, of which the rectum 

 5^ ; cceca -j^. 



