REPORT ON THE SPHENISCID^. 201 



The Spleen. 



The spleen of Eudyi^tes chrysocome (PI. XVI. fig. 5) from Tristan d'Acunha, as well 

 as in specimens from the Falklands and Kerguelen Island, is of a reddish purple colour, 

 and presents the form of a flattened oval cake, measuring 1 inch in length, ^ an inch in 

 greatest breadth, and ^ of an inch in thickness. It lies to the right side of, and behind 

 the termination of the oesophagus, being situated in front of the upper end of the left 

 kidney, and in close relation to the under surface of the liver. In the female it lies in 

 front of the ovary. It is supplied with blood by a branch from the coeliac axis. The 

 veins carrying back the blood to the heart open into the portal vein. 



Variations in respect of the Spleen. 



The spleen, as might be expected, varies much in size, not only in different species, 

 but in difi'erent specimens of the same species. In one specimen of JEudyptes chrysolophiis 

 (PL XVI. fig. 6) the organ presented the form of an oval flattened cake, measuring 1 

 inch in length and ^ an inch in greatest breadth, while in another specimen it was 

 oblong in form, and measured 1 inch in length, ^ of an inch in breadth, and the same 

 in thickness. In Spheniscus demersus the spleen is proportionaUy larger than in 

 Eudyptes. In one specimen it measured 1^ inches in length, 1 inch in breadth, and 

 ■Jth of an inch in thickness, and presented an irregular outline ; while in a second 

 specimen (PI. XVI. fig. 7) the viscus was of an elongated oval form, the extremities of the 

 oval being pointed. In this specimen the spleen measured 2^ inches in length and f 

 of an inch in greatest breadth. 



In Spheniscus magellanictis (PL XVI. fig. 8) the spleen measured 2 inches in length, 

 f of an inch in breadth, and ^th of an inch in thickness. In Spheniscus mendicidus, 

 unfortunately, I failed to note the dimensions of the organ. In Spheniscus minor 

 (PL XII. fig. 5) the spleen is kidney-shaped, and measures f of an inch in length and ^ of 

 an inch in breadth. The spleen in one specimen of Pygosceles tceniatus was circular in 

 form, and of the size of a farthing, while in a second specimen (PL XVII. fig. 3) it 

 measured 2 inches in length and ^ an inch in greatest breadth. In form the spleen 

 of the second specimen was somewhat crescentic, the convex margin being directed 

 toward the right side of the bird. Lastly, in Aptenodytes longirostris (PL XVII. fig. 4) 

 the spleen presents the form of an almost circular flattened cake, measuring 1 inch in 

 diameter and \ an inch in thickness. 



In every species in which the spleen presents an elongated form, the long axis of 

 the viscus in the natural position of the organ coincides with that of the body of the 

 bird. 



(zooL. CHALL. EXP. — PART xvm. — 1883.) S 26 



