NOTES ON DISTOMA ENDEMICUM. 53 



ovary and vitellarium can be discerned as whitish objects. 



The total length of the body averages 1 If mm. The largest 

 measured 13 mm. and the smallest 8 mm. in length. At about the 

 middle of the body, the breadth measures 2 — 2| mm. (Kiyono &c. 

 give 8—20 mm. x 4 — 5 mm. and Baelz 8 — 11 mm. x 3.5 — 4 mm. 

 for the dimension). It has thus an elongated form resembling Dist. 

 lanceolatum in shape. In fig. 1 I have endeavored to reproduce the 

 shape as exactly as possible. The anterior portion occupying about |- 

 of the whole body-length tapers toward the blunt apex where the 

 mouth is' situated. This portion of the body is marked off from the 

 hinder portion by a slight curving in of the sides. At the level of 

 these notches is situated the ventral sucker ( v. s.), at which point the 

 breadth of the body measures IJ — 1 g- mm. Behind the ventral sucker 

 the body is broad and flat. The ventral side is more convex than 

 the dorsal, while in front of the ventral sucker the cross-section of 

 the body presents an oval form. The hind end does not taper away 

 so gradually as in front, but forms a rounded angle of about 90° 

 or less. 



The skin ( " Cuticula " ) is smooth, very thin and without spines. 

 Its substance is finely granular. Much controversies were held as to 

 the nature of " cuticula^ Biehringer* and Schwärzet have lately 

 shown that it originally constitutes a layer of nucleated cells (ectoblast), 

 an opinion that I can fully corroborate. 



The peripheral system of muscles (HautmuslcelscMcht) is weakly 

 developed. It consists of a layer of exceedingly fine circular fibers 

 lying in immediate contact with the skin, a middle layer of strong 

 longitudinal fibers, and an innermost layer of less developed diagonal 

 fibers. Dorso-ventral fibers are rather abundant. 



The mesenchy matous connective tissue presents the usual aspect. 



*Beitr. z. Anat. li. Entwickl.-gesch. d. Trematodea. Arbeiten aus dem Zool. Inst, zu 



