IRWIN-SMITH. 



425 



of the stomach preserved, whether they were on the outer or inner side of the 

 wall. But microtome sections, made by Dr. J. R. Dixon, show that they are all 

 quite external, being situated between the muscle-coat and a thin, transparent 

 membrane, which is evidently the peritoneum. They are not embedded in the 

 muscle, but lie loosely on its surface, in depressions which are sometimes deep 

 enough to displace the muscle fibres (Text-fig. 32). When the peritoneum is 

 stripped off, they are easily detached intact, each enclosed in a tough, but very 

 thin, smooth, and semitransparent membrane, within which the coiled nematodes 





Figs. 30-38. Encysted Physaloptera larvae on stomach of Hinulia taeniolatum. 



30. Portion of stomach-wall of host, with Physaloptera cysts (x 7.5); 31. A 

 single cyst (x 27); 32. Transverse section through cyst, and stomach-wall (x 30); 

 33. Anterior end of nematode, showing junction of muscular and glandular 

 oesophagi, nen,'e-ring, and post-cervical papillae (x 100); 34. Internal view of lip 

 (x 190); 35. Physaloptera sp. Whole worm uncoiled (x 27); 36. Junction of 

 oesophagus and intestine (x 100); 37- Female tail (x 100); 38. Male tail (x 100). 



lie free in a watery medium (Text-fig. 31). The cyst -wall, appai-ently, has no 

 connection with the host-tissues. It consists of a thin outer layer of loose cel- 

 lular tissue, strengthened, internally, by a thicker, denser layer of fibrous material. 



