136 ON THE STOMACH IN TANAGERS. 



any external diverticulum to be seen ; and I therefore can only conclude 

 that Lund must have been misled, he, owing to the bad condition of 

 his specimens (a very probable contingency when dissections are made 

 in tropical climates), having mistaken a bit of fat or connective tissue 

 for a diverticulum of the ventriculus, which last there can be no doubt 

 that this non-glandular zone really represents, the muscular walls and 

 hard epithelium of the true Passerine gizzard being almost entirely 

 undeveloped *. 



1 have also been able to ascertain that the nearly allied genus Chloro- 

 phonia (at least in C. viridis) is characterized by the same non-develop- 

 ment of a gizzard. On the other hand, all Tanagers yet examined 

 belonging to other than these two genera have stomachs constructed on 

 the normal type. Thus in a specimen of Tachyphonus melaleucus (see 

 fig. 1, p. 134) the characteristic gizzard with the two central tendons is 

 present and well developed, the muscular walls being nearly | inch thick, 

 and the epithelium lining it hard and horny. As might have been 

 expected, considerable variations in the comparative development of these 

 parts occur in different genera. Thus in the thick-billed Pitylus the 

 P Z S 1880 wn l e organ is much more strongly developed than in the more slender- 

 p. 146. billed genera Tanagra, Calliste, &c. Why the genera Euphonia and 



Chlorophonia alone, as far as it is yet known, of birds should present 

 this structure is an as yet unsolved problem ; I believe they differ in no 

 appreciable degree from other Tanagers in food f or habits. I may also 

 remark that in such genera as Coereba and dEthopyga, feeding chiefly on 

 minute insects and juices of flowers, there is a well-marked gizzard, with 

 muscular walls and hardened epithelium. 



Subjoined is a list of all those species of Tanagers, 27 in number 

 belonging to 11 genera, in which the condition of the stomach is as yet 

 known. This includes the species mentioned by Lund (L.), as well as 

 those examined by the late Prof. Grarrod (A. H. Gr.) and myself, and 

 the nomenclature is that of the * Nomenclator/ Mr. Sclater having 

 kindly reduced Lund's names to the terms of that list for me. 



* In confirmation of the above-mentioned view being correct, I may notice that 

 neither Owen (Anat. Vert. ii. p. 106) nor Gadow (Jen. Zeitschr. B. xiii. p. 168, 1879), 

 when mentioning the stomach of Euphonia, describe any lateral diverticulum. Prof. 

 Garrod, in his MS., notes of Euphonia violacea, with characteristic terseness, " No 

 stomach specialized, the intestines apparently continuing from the oesophagus." 



t Several of the wild specimens of Euphonia that I have dissected have had in their 

 intestines a large number of small round reddish seeds, which are probably, Mr. 

 Salvin tells me, those of a climbing species of Ficus common in the Central-American 

 forests. 



