50 



s. GOTO. 



body, while individual variations in this respect may he almost imper- 

 ceptibly small. iSTear either end of tlie body the endoparenchyma 

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

 tissue, interspersed with nuclei (PI. IT, fig. 7 ; PJ. IV, fig. 2 ; PI. 

 XII, figs. 4 & 7 ; PI. XY, fig. S ; PI. XVI, fig. 1). In other parts 

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

 of differentiation of the original mesenchyma cells. Some of these cells 

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

 fibres of the connective tissue ; while (3thers 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 <3f the body, and also in different species. An endo- 

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

 in Microcotijîe sciaenac, Calicotijlc Mitsulurii, and in the terminal por- 

 tions of the l)ody of many other species ; that of a true syncytium we 

 have found in Trislomum siimatum and ILwacofijIe (jrosm ; while in all 

 the other species the syncytial and fibrous characters are variously 

 interminHed. 



6. The Digestive Sijstem. 



The digestive system consists of the mouth and its cavit}', the 

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

 connected with them. 



The rnovtli is a funnel-shaped opening situated, in all the species, 

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

 Microcot[/le, Axine, Oncliocofiih', Dididopltom, Octocotijie, and Hexacoti/le, 

 it is close to the anterior end of the body ; while in Tristoinum, EpiJ)- 

 ddhi, MonocotijJe, and Cidicoli/lc it is more distant from it. In most 

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



