50. S. GOTO. 



body, while individual variations in this respect may be almost imper^ 

 eeptibly small. Near either end of the body the endoparenchyma 

 consists, in almost all species, of typical, fibrous, reticulated, connective 

 tissue, interspersed with nuclei (PL II, fig. 7 ; Pi. IV, fig. 2 ; PI. 

 XII, figs. 4 & 7j PI. XV, fig. 8; PI. XVI, fig. 1). In other parts 

 of the body we may distinguish two diiferent tendencies in the course 

 of difterentiation of the original meaenchyma cells. Some of these ceUs 

 appear to assume more of a vacuolated character, and these furnish the 

 fibres of the connective tissue ; while others come to have more and 

 more a granular protoplasm without any distinct membrane, and to 

 form finally a continuous syncytium by simple obliteration of their 

 boundaries. These two tendencies prevail in different degrees in 

 different parts of the body, and also in different species. An endo- 

 parenchyma of a typical, reticulated, connective tissue we have found 

 in Microcoti/le sciaenaeyCalicoUjle Mitsulcurii, and in the terminal por- 

 tions of the body of many other species ; that of a true syncytium we 

 have found in Tristomwn sinuatum and Hexacotijle grossa ; while in all 

 the other species the syncytial and fibrous characters are variously 

 intermingled. 



*o* 



6. The Digestive System. "■ 



The digestive system consists of the mouth and its cavity, the 

 pharynx, the oesophagus, the intestine, and the glands which are 

 connected with them. 



Tlie mouth is a funnel-shaped opening situated,' in all the species, 

 on the ventral side near the anterior extremity of the body. In 

 Microcoti/le, Axiiie, Onchocotijle, Diclidophora, Octocotyle, and Hexacotijle^ 

 it is close to the anterior end of the body ; while in Tristomum, Epib- 

 della, Monocotyle, and Calicotyle it is more distant from it. In most 

 species there is a tolerably ample mouth-cavity ; and in those forms 



