80 MR. F. E. BEDDARD ON THE 



to one side, in the middle of its course. It looks, in fact, as if two 

 originally distinct loops were in process of reduction to one. The 

 consideration of this specimen, therefore, renders another com- 

 parison possible, namely with the Cranes *, for in these birds the 

 jejunum has three separa.te loops. In other respects, the third 

 example of Frritercida arctica agieed entirely with the other two. 

 Apart from possible resemblances to other groups of birds that 

 have been indicated, the gut of Fratercida shows a feature of 

 particular interest in the great length and irregular disposition of 

 its ileic region. This latter is quite unattached to the duodenal 

 loop, except perhaps at the very base ; it is long and lies loosely 

 coiled like the Mammalian small intestine. It is, in fact, the 

 loiigest section of the gut. This bird, in fact, shows an intestine 

 constructed in a way which is exactly opposite to that which is 

 prevalent in the class Aves. When there are tracts of primitive 

 undifferentiated small intestine left it is nearly always the jejunum 

 that is involved, and not the ileic region. In Fratercula the 

 jejunum is specialised into fixed loops, while the ileum has 

 remained unspecialised. Indeed, my experience of this structure 

 among birds has only furnished one example at all parallel to the 

 gut of Fratercula arctica. 



This was an example of the Pheasant, Exiplocatmis nyctlienierus. 

 The Gallinaceous birds (see p. 55) ai-e very uniform in the 

 disposition of their intestinal tract, and one out of two examples 

 of this species which I have dissected was perfectly normal in the 

 structure of the gut. A second individual, however, differed. 

 The duodenal loop was immediately followed by a straight, stiffly 

 fixed, descending tube of intestine, which bent back upon itself for 

 a short distance and then passed into a long loosely coiled region, 

 a kink became continuous ultimately with the straight portion 

 of the ileum running to the junction with the cteca. This coiled 

 region of the gut, although lying on the left side of the body, was 

 not in any way attached to tlie duodenum. Thei'e is, therefore, 

 here, it will be seen, a reversal of the conditions found generally 

 among Gallinaceous birds. In this example of Fitplocamus 

 nycthemerus the stiff descending intestine which immediately 

 follows the duodenum obviously represents in one sense the 

 equally stiff ascending piece of intestine which is in the other 

 example of E. nycthemerus, and also in other Gallinaceous birds, 

 parallel to and partly fixed by ligament to the duodenal loop ; 

 while in the latter the loose coils which form the major part of 

 the small intestine lie to the right hand. There is, in fact, a pre- 

 cise reversal of the " normal " conditions. There is, as I think, an 

 undoubted resemblance between this " abnormal " example of 

 Eziplocamus nycthemerus and the normal arrangement of the 

 intestinal tract in Fraterctda arctica. 



PoDiciPEDES. — I cannot quite explain by means of Dr. Mitchell's 

 figures the intestinal loops of the two Grebes Tachyhaptes 



* Vide p. 82. 



