lA'TESTINAL TRACT OF BIRDS. 



241 



L:iri(la', are (lerivatives of the pattern only sli-litly niodiCied l)y increased length. A 

 nioditication of the Limicoline-Gruiform metaceutre is found in many of the simpler 

 Cliaradriidse such as Numenius, and consists in the gradual shaping of Meckel's tract 

 into three loops and a supra-duodenal looj). Of tlic three, one is axial and carries a 

 large diverticulum on its distal limh. From this Charadri-Gruiform metaceutre one line 

 of •progressively increasing apocentricity, consisting chiefly in a lengthening of the axial 

 loop, is attended hy degeneration of the caeca; it runs through Trhiga and liccKrviroslra 

 to Scolopax. The Gruiform metacentre is another ajjocentric derivative of the Charadri- 



¥\v^. 50. 



Olidid.i 



'kirddriid* 



Charadriidas 



Rhinochetu 



Eurypvg 



Columbidae 



Gruin# 



Charadrndc 



Gruiform 

 MeLdCentre 



OpisLhocomus 



Pterocles 



Tinanu 



Chioiiidat 



La^ 



Lari 



Araiiudae 



Chat'ddri-Gruiform 

 MetacenU^ 



CEdicnemidcS 

 Glareolidas 

 inocondae 

 Parridae 



imicohne- 



Gruifonn 



Metacentre 



Palamedea 

 ArchecenLre 



Mvohitioii (if the Intestinal Tract in the Alectoromorphine Legion. (For UelorornU read Beliornis.) 



(iiuiform mttaccutie, and is reached hy the first three loops of Meckel's tmct, including 

 the axial loop, heing more clearly marked otf and lengthening equally. Most of the 

 I'allidte rtmiain in this condition. The Gruinae are apoccntric modifications of it in 

 which all tlie loops, except that immediately following the axial loop, increase in length 

 individually. The Psophiina; and Heliornithidtr are practically unmoditied from it. 

 Ilhhwchetii.s is modified only in that the first loop of Meckel's tract is represented hy 

 two loops, and that the ca'ca are reduced. Eurij\>ii<i(i is more modified, its apjiarent 

 simplicity heing almost certainly secondary. The Uicholophidae and the Otididae arc 

 very apocentric modifications of it, the apocentricity consisting chiefly in the reduction 



