272 PEOTBNTEICULAK CETPTS OF PSEUDOTANTALUS IBIS. [Mar. 19, 



and conspicuous apertures of the glands, and the two circular areas 

 form thick pads that may be seen and felt from the outside before 

 the stomach is opened. The figure in the text (p. 271) represents 

 the proventriculus laid open, with the two circular areas conspi- 

 cuous opposite the reference letter b. Above these, in the African 

 Tantalus, is a single irregular row of pits, of different sizes and 

 about twenty in number. In the figure the row is shown opposite 

 the reference letter a, and at d an enlarged view of one of them 

 is given. There is no tra,ce of these pits or crypts in the other 

 birds with similar proventriculus that I have examined. Each 

 crypt is a shallow circular or oval pit, the margin of which is 

 slightly elevated. From the floor of the crypt rise a system of 

 crescentic folds of different sizes. 



As the bird was tolerably fresh when I examined its intestine, I 

 prepared microscopic sections through one of the crypts. The 

 drawing (Plate XVII. fig. 1) represents one of these seen under a 

 low power, e, f, and // are placed opposite the ends of the cres- 

 centic folds, the letter^ being placed within the cavity of the crypt. 

 The surface of these folds is set thickly with a number of small 

 villi, and these are continued over the raised margin of the wall 

 of the crypt. Fig. 2 represents some of these villi seen under 

 higher magnification. 



The whole of the pit is lined by an epithelium continuous with 

 that lining the general surface of the proventriculus (fig. 1, ej), 

 fig. 2, e^), k & m). Over the general surface this is an ordinary 

 columnar epithelium, but here and there between the villi, as at 

 5/(, it becomes glandular. At fig. 2, h, two of these glandular 

 infoldings are seen in cross-section. Immediately under the 

 epithelium seen at a, in fig. 1, and forming the solid mass in tig. 2, 

 is a dense connective-tissue layer. This contains fibres and cells, 

 and here and there capillaries and absorbents . This layer forms 

 the greater part of the villi and lies next to the epithelium on the 

 summits of the crescentic folds. But further down, in the cavity 

 of the crypt, masses of lymphatic tissue (fig. 1, c) lie between the 

 connective tissue and the epithelium. Here and there bands of 

 connective tissue invade the masses of lymphatic cells and separate 

 islands of them from the main mass. This layer of lymphatic 

 tissue was the most conspicuous part of the sections, and as in some 

 of them the epithelium had been destroyed it closely resembled a 

 granular cuticular layer. 



Under the connective-tissue layer was a thicker layer consisting 

 of a loose stroma containing fibres, connective-tissue cells, and 

 blood-vessels. 



The deeper part of the section (fig. 1) passed through some of 

 the follicles of the proventricular glands. Each of these was 

 surrounded in the ordinary way by a capsule of connective tissue. 

 I confess that I am unable to form any clear conception as to the 

 function of these crypts. It is possible that they may serve for the 

 absorption of water or of fluids. From the position of the stomach 

 in the body, these crypts must He very little above the level of the 



