ANATOMY AND PHYSIOLOGY OF PATELLA YULGATA. 609 



side, and the renal and anal papillae on the other. The pharynx widens consider- 

 ably after becoming free from the buccal mass, and two deep pouches, the 

 continuations of the lateral divisions of the pharynx, lie on either side of the 

 neck in front of the salivary glands. The so-called " crop " (the name is very 

 inappropriate) is a long thick- walled sac continuous on the one side with the 

 pharynx, on the other with the oesophagus. The folds in the pharynx are con- 

 tinued to the crop, which has other transverse folds of its own. The interior has 

 been justly likened to the maniplies of a sheep's stomach. Round the "crop" 

 and the true stomach, which lies above it, is the liver, an irregular yellowish 

 mass which fills up all the intervening space between the " crop," stomach, and 

 coils of intestine soon to be mentioned. It is a compound tubular gland, 

 supported by a framework of connective tissue. The biliary secretions appear 

 to be poured into the crop at many points ; more accurate information must be 

 obtained, however, with reference to that point. The oesophagus is of small 

 and uniform diameter; it makes one short coil on the floor of the visceral 

 cavity and then widens into a long stomach, which is doubled on itself, and lies 

 across the centre of the body (when not displaced by the greater size than 

 usual of the genital gland), the blunt or folded end lying behind the peri- 

 cardium, but usually separated from that by one or two folds of intestine. The 

 two halves of the stomach are closely applied. From the pyloric end of the 

 stomach the intestine springs, and maintains throughout its entire length a 

 constant diameter, viz., about equal to that of the oesophagus. The intestine 

 immediately after leaving the stomach bends sharply back and runs beneath the 

 folded end of the stomach round to the head, passes in front of the cardiac 

 portion of the stomach, over the buccal mass, and, on reaching the extreme 

 edge of the visceral sac on the left side, bends sharply upwards, and coils over 

 a subsequent loop of intestine. It then forms a superficial loop on the dorsal 

 surface, over the top of the stomach, passes again back to the point at which it 

 bends upwards, and there bends downwards. The ascending and descending 

 portions touch one another at that point. The intestine then travels along the 

 floor of the visceral sac, and, after making a complete circuit of the sac, passes 

 forward, and, curving backward once more, forms that portion of the intestine 

 which is looped over by the ascending and descending parts above mentioned. 

 It makes one more complete circuit of the visceral sac, and then ends at the 

 anal papilla on the right shoulder. 



The columnar epithelium of the exterior epiderm is continued into the 

 interior of the alimentary canal. The pharynx is lined with columnar epi- 

 thelium resting on a layer of connective tissue and muscle. Over the roof of 

 the pharynx, both in the central and in the lateral divisions, there are many 

 convoluted compound tubular mucous glands. The secretion of these glands, 

 which is poured into the buccal cavity, is thick and viscous, and contains many 



VOL. XXXII. PART III. 5 I 



