PLATANISTA. 445 



are 0-05 inch in diameter. The rim of the cup is not its greatest diameter, which is 

 attained about the middle. These single cups in the adult are also connected to each 

 other by strands of mucous membrane. 



Microscopic characters of the second cavity. — This is clothed with cylindrical 

 epithelium, and in its whole extent is densely clad with tubular glands, into which 

 the cylindrical epithehum is prolonged. These glands form a layer about one-eighth 

 of an inch in thickness, and they are so closely packed together at their open 

 extremities that the interspaces between equal only half the breadth of a gland 

 tubule. They are simple tubes in the first half of their extent, but they then divide 

 into two branches, and in some instances bend suddenly before the division. These 

 secondary branches rapidly diminish in capacity, and are soon reduced to narrow tor- 

 tuous tubules which run vertically downwards, but more or less parallel to eacii 

 other, and are lodged in a thick layer of corpusculated connective tissue. They 

 appear also to give off other branches like themselves maintaining a similar course. 

 The divisions can be undovibtedly observed, but they are not so numerous as one 

 would expect. I am not, however, prepared to say that they are all racemose 

 glands, but if simple ones occiu, they would appear to be the exception and to differ 

 only from the compound glands in being unbranched. It appears to me as if the 

 glandular tubules depending from a common duct were bound up in one sheath, 

 because I observed even as many as from two to four orifices, in oblique section, lying 

 together as if in a cellular mass, external to which were the upward prolongations 

 of the muscular mucosa. These cells around the tubules are large ovoid vesicles, 

 with well-defined rounded nuclei, and, as they were unstained by hsematoxylon, 

 they are difficult to demonstrate. They are doubtless the peptic cells seen through 

 the delicate membrana propria. The cyHndrical cells lining the ducts and their chief 

 branches, and occurring in the interspaces between the orifices of the ducts, have 

 finely granular contents. In the hollows between the convolutions of this cavity, 

 the peptic glands are larger tubes than on the convolutions, but shorter and more 

 branched. 



What I have termed cup-shaped bodies of this second gastric cavity I further 

 examined by the microscope, both in vertical and horizontal section. They are 

 altogether very pecuhar and quite anomalous structures, and I have represented them 

 in figs. 1 and 2, PI. XXXVII. In the vertical section (Kg. 1) they partially occupy 

 the glandular layer, but seem quite distinct and cu'cumscribed from the adjoining 

 tubular mucous glands. In the vertical section, they present a homogeneous 

 or faintly granular egg-shaped outer area, and centrally a darker ovoid mass, 

 also vertically placed. Whether by refraction of the hght, or otherwise, in this 

 ^dew there seems to be a central band in the long direction of the inner object. In 

 the transverse or horizontal sections (Fig. 2) these cup or egg-shaped bodies exhibit 

 a thick circular outer wall, with an inner lining to the same. This latter is bent 

 inwards chiefly in three, or occasionally in four, angular pieces projecting midway 

 to the central open space. They, therefore, cause the interior to have a trifoil 

 area and where they almost meet divide the space into as many nearly circular 



