144 MR. W. A. FORBES ON THE STRUCTURE [Mar. 2, 



As was first pointed out by Lund, half a century ago, a singular 

 exception to this rule obtains in the Tanagers of the genus Euplionia}. 



From his description (quoted below) and figures, it is quite 

 evident that Lund considered that there was, in these birds, an in- 

 termediate zone devoid of glands or muscles, between the proventri- 

 culus and the commencement of the small intestine, and that a small 

 lateral diverticulum springing from this zone was also present, re- 

 presenting the true, though rudimentary, gizzard. Lund found, as he 

 believed, this state of things in three species of Euphonia, whilst the 

 normal type of stomach existed in sixteen other species of Tanagers 

 which he examined. Lund's description has frequently been copied 

 since in various text-books, and his figures at least three times re- 

 produced^. 



Mr. Sclater, having called my attention to this subject, I have been 

 able, thanks to the resources of the Prosector's department and to the 

 material afforded by Mr. Salvin, to reexamine this question. I have 

 been able repeatedly to dissect specimens of various species of 

 Euphonia, both preserved in spirit and quite fresh. I can fully 

 confirm Lund's description in all points, except as regards the pre- 

 sence of a small lateral diverticulum from the alimentary canal, of 

 which I have never been able to find the slightest trace, though I 

 have always carefully looked for it. 



Fig. 2 (p. 145) will show the structure of this part of the alimentary 

 canal, with the parts as little disturbed as possible, but with the stomach 

 &c. cut open from behind, in a perfectly fresh specimen of Euphonia 

 violacea. As will be seen, between the glandular proventriculus and 

 the villi-covered duodenum a narrow zone is interposed, with its walls 

 in no degree thickened, but thin and membranous, and of rather greater 

 calibre than the adjacent parts, there being no pyloric constriction. 

 Moreover there is none of that approximation of the cardiac and 



^ In a pamphlet entitled " De genere Eiiphon.es, prsesertim de singular! ea- 

 nalis intestinalis struotura in hocee avium genere, autore Dr. Peter Wilhelm 

 Lund," published at Copenhagen in 1829 (31 pages and 1 plate). 



This pamphlet being rather scarce, I here give Lund's own words : — 



" § 13 (p. 12). Ubi incipit intestinumtenue, ibi conspicitur in externa super- 

 ficie augustae illius zonce, qu£e locum ventriculi occupare videtur, minima qua;dam 

 protuberantia, cui intus respondet levis qua3dam imjjressio. Opaca est parvula 

 haec protuberantia ; quare in parietibus fibras musculosas contineat non dubito ; 



hoc vero, propter minimam ejus molem, decidere vis valebis Ad earn 



sententiam maxima inclinare animam, ut statuam verum esse hoc ventriculi 

 analogon, baud diffiteor. 



" § 14. Hsec si vera judicetur cogitandi ratio, referas licet structuram hujus 

 avis ad formam avium generalem ; ita enim habebimus, uti solet, musculosum 

 nostrum organon e latere intestini exortum, interque proventriculum et inte- 

 stinum tenue positum ; neque a forma generali avium aberrat hsBC struotura, nisi 

 in eo, quod ad minimum quoddam rudimen turn reductusestventriculus: contra, 

 si zonam illam, de qua mentionem fecimus, angustam pellucidamque, qua inter 

 proventriculum et intestinum tenue invenitur, analogon esse ventriculi statua- 

 mus, constantes duo maximeque essentiales ventriculi avium characteres sub- 

 ruentur, in museulosa structura^ortuque laterali positi." 



» Oarus and Otto, Tab. Anat. Comp. Llustr. 1835, pt. iv. tab. vi. figs. 4, 5 ; 

 Wagner, Icones Zool. iii. t. xi. figs. 3, 4; Bruhl, Zoot. aller Thierkl. Lief. iii. 

 pi. ix. fig. 13 a. 



