On Aspidogaster riugens (Linton) and A. kemostoma n. sp. 253 



of the anterior end of tlie bod}^, may act as a kiiid of sucking- 

 apparatus. 



The prepharyngeal part of the Oesophagus is rather long and 

 very thinwalled. It is provided with delicate longitudinal muscle 

 fibers and toward the pharynx five or six rings of circular fibers. 

 The Pharynx is a cylindrical thick musciilar ring with a delicate 

 refractive lining membrane. Anteriorly it is bevelled outward to 

 the Oesophagus and this concave bevelling is surrounded by a group 

 of muscle fibers which run pai-allel to its inner surface. Elsewhere 

 it has an inner layer of thin ring fibers and an outer layer of 

 coarser flat ring fibers. The remainder consists of abundant radially 

 arranged fibers of finer character. Just behind the pharynx the 

 Oesophagus merges into the simple intestine which runs as a Single 

 tube to a point near the posterior end of the body. Throughout to 

 its blind end it is smooth and thin walled and supplied with delicate 

 longitudinal and circular muscle fibers. It is lined with rather high 

 cuboidal epithelium. 



The ventral sucking disc has a peculiar structure. It is elevated 

 on a soft mass of the body parenchyma through which run 

 numerous long stout muscle bundles to reach its muscular wall. In 

 sagittal section the whole mass appears as a projection from the 

 rest of the body the ventral surface of which is in occupied by 

 a continuous series of sucker like structures over the surface of 

 all of which the cuticle runs. Each of these cups which represent 

 the depressions seen on the ventral surface of the disc has 

 practically the structure of a sucker. There are fine subcuticular 

 transverse muscle fibers, a predominant mass of a radial fibers, 

 but no external transverse or longitudinal fibers. A\here the cups 

 adjoin one another, the separating ridge is composed at its crest 

 of a bündle of short fibers extending longitudinally as though to 

 connect one cup with another. This condition alone is to be 

 found in the more central part of the disc, but around the 

 margin the little triangulär space which lies beneath this connecting 

 band of muscles is found to lodge a finely granulär and fibrillated 

 mass which probably represents the sense organ so frequently noted 

 in such forms. From these structures there generally runs a fibril 

 probably of nervous character to the inferior of the body. Such 

 bodies show no evident ganglion cells but have the general appearance 

 of the nervous tissue seen in the large ganglia. They send a 



