COLUMB^ 



307 



pigeon showing a more normal state of affairs. There are 

 four muscular pads in its walls, so that in transverse sections 

 the lumen is cruciform. In Ptilopus coronulatus the lumen 

 of the gizzard is not regularly cruciform, Hke Ft jambu, 

 but irregular and asterisk-shaped; so with Ft. superbus. 

 Chryscena viridis has also a ptilopine gizzard. In Carpo- 

 phaga paulina the transverse section shows a close approach 

 in the structure of its gizzard to that of Ptilopus. In C. 

 latrans (fig. 155) the gizzard is lined with extraordinary 

 conical horny processes.' The right lobe of the liver is 

 larger than the left, and 

 the gall bladder may be 

 absent or present. 



' In the Columbse 

 which I have examined 

 (Columbm of several 

 species (fig. 156), Fhlo- 

 gcenas cruentata),' re- 

 marks Mr. Mitchell, 

 ' it is tempting to regard 

 the gut as a simple deri- 

 vative of the type seen 

 in Fterocles. The duo- 

 denum is longer and 

 narrower. The circular 

 loop is enormously ex- 

 panded, but the three 

 subsidiary loops seen 

 in Fterocles remain. The first of these is somewhat shortened ; 

 the second, that- bearing the yolk-sac vestige at its end, is 

 enormously lengthened ; the mesentery is folded along the 

 line of the median mesenteric vessel, so that the two limbs 

 of the loop are brought in contact with each other, and, 

 finally, the whole folded loop is rolled into a rough spiral. 

 The third subsidiary loop of the circular part of the gut has 



' E. Gekmain, ' NDtesurla Structureiu Gfeierohez le Pigeon Nioobar,' Ann- 

 Sci. Nat. (5), iii. p. 352 ; Gabkop, .' Note on the Gizzard and other Organs of 

 .Carpophaga latrans,' P. Z. S. 1878, p. 103. : 



X 2 



Fig. 156. 



—Intestines of Columba Uvia 

 (aptek Mitchell). 



