1874.] VOMITED BY HORNBILLS. 423 



families of birds (strato epiteliale, Molin) is composed of a corneous, 

 and, in thin slices, pale yellow transparent substance. The lower 

 surface of this lies upon the subjacent follicular layer (Flower), the 

 former dovetailing with the papillae of the latter. As the horny 

 layer ascends it exhibits a series of vertical, parallel, and cylindrical 

 columns, each homogeneous in composition and with intervening 

 epithelio-granular substance. Towards the free surface the columnar 

 character ceases, and is replaced by loosely arranged epithelium-scales. 

 In some genera of birds the columns are found to be tolerably regu- 

 lar and equidistant ; in others they are more unequally distributed or 

 form aggregated groups. 



A portion, though, I find, (not the whole) of the large sac obtained 

 from the Subcylindrical Hornbill corresponds in its minute structure 

 with the above description in every particular. In the vertical section 

 (A, fig. 2, p. 424), and more highly magnified portion of the same (B), 

 short tubular prolongations are observed inferiorly. These, in some 

 instances, have a compound character terminally, while optically 

 deeper or beyond them others similar in kind are visible. By dif- 

 ferent focusing of the object, a granular and partly fibro-cellular 

 thin connective layer is seen, moreover, to invest the tubes just above 

 their free ends. This produces an appearance suggestive of the lower 

 extremities, seeming tubules, being short, compound, granular flasks, 

 which decidedly they are not, but only the unequal extension of the 

 homogenous pillars above mentioned. These latter, in this perpen- 

 dicular view, are long rods barely to be distinguished from the inter- 

 mediate substance, on account of the latter being less transparent. 

 At different levels, more defined indications of horizontal stratifica- 

 tion or lamellar layers obtain. At the top of the rods there is a 

 copious development of large nucleated and granular columnar epi- 

 thelium. Here and there also some of the tubules have been 

 squeezed out, and, along with the narrow ends of epithelial scales, pre- 

 sent an irregular fringed margin. In the horizontal sections of the 

 same object (C, D, E), the solid nature of the rods is manifest, and 

 it becomes abundantly evident that several rods (averaging 4 to 5) 

 lying in apposition constitute a column or cylindrical bundle. These 

 latter are dispersed at tolerably equidistance, though not precisely 

 regular in contour or calibre ; and this causes a grade or variety in 

 the pattern. From the difficulty of cutting a perfectly flat, uniform 

 section, a partly tangental one occasionally results ; but this more 

 clearly shadows forth the coalescence of the homogeneous rods, and 

 how their aggregation into pillars is effected. At other places it like- 

 wise admits of the molecules and nucleolar-celled character of the 

 intercolumnar tissue being studied. 



With regard to the other smaller sac, I have not been fortunate in 

 my search to obtain tissue answering to the above cylindroid charac- 

 ter, but find it simpler or less differentiated in its elements, agree- 



larged vertical section through all the coats of the stomach of the Heron, which 

 well enables the relations of the strata to one another to be studied. Klein, in 

 his articles "(Esophagus "and "Stomach" in Strieker's 'Manual,' pp. 536 & 554. 



