458 DIGESTIVE SYSTEM OF THE OX 
ventral and lateral margin of the large, oval rumino-reticular orifice (Ostium 
rumino-reticulare). The medial margin of the fold, if continued, would end about 
at the cardia, but there is in this region no demarcation between rumen and reticu- 
lum; hence it is termed the atrium ventriculi. 
The lateral border of the rumino-reticular fold ends above the level of and behind the plane 
of the cardia, the medial one Just behind the @sophageal groove and about four to five inches 
lower down. Undoubtedly food or water swallowed with even a small degree of force passes first 
into the rumen. Foreign bodies (which are commonly swallowed by cattle) are, however, found 
in the reticulum. 
The cardia is opposite the seventh intercostal space or eighth rib, a little to the 
left of the median plane, and about a handbreadth (ca. 10-12 em.) ventral to the 
vertebral column; it is not funnel-shaped. 
The mucous membrane of the rumen is brown in color, except on the margins 
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Fig. 390.—ReticvLumM oF Ox, FROM PHOTOGRAPH. 
The specimen was cut along the greater curvature and laid open by reflecting the anterior wall. C is the cardia. 
The arrow points to the reticulo-omasal orifice. The spiral twist of the cesophageal groove was of necessity partly 
undone by reflecting the wall; its lips are drawn apart, showing some of the peculiar birdelaw-like papille in the 
ventral part. 
of the pillars, where it is pale. It is for the most part thickly studded with large 
papillee, many of which are nearly half an inch (ca. 1 em.) long. The edges of the 
chief pillars and a large part of the wall of the middle of the dorsal sac are, however, 
not papillated. The papillary arrangement is most developed in the blind sacs. 
The papille vary much in size and form; the largest are foliate, many are narrow 
or filiform, and others are conical or club-shaped. The mucous membrane on the 
medial wall of the atrium is finely wrinkled and non-papillated, while dorsally and 
laterally it is papillated. The papillary arrangement also extends over the edge 
of the rumino-reticular fold an inch or two (ca. 2 to 5 em.). 
The cesophageal groove (Sulcus cesophagus) begins at the cardia and passes 
i 
