163] PROTEOCEPHALIDAE—LA RUE 163 



margins of the quadrants often are indented especially on the flattened 

 sides. The furrows, especially the heavier median ones, arise in the 

 region of the first proglottids. In each quadrant a deep rounded sucker 

 is sunken which lies nearer the margin of the scolex than to its tip. 

 Two types of scolex are recognized with intermediate forms. The one 

 is more or less flattened on the anterior face. It has a more or less 

 round cross section. Its furrows are shallow, and its suckers are di- 

 rected anteriad while the other type has an elliptical transverse section. 

 Its thickness is less than the breadth of the scolex. The scolex itself is 

 much flattened. The furrows are deep and very plain, reaching nearly 

 to the tip of the scolex. The suckers are more elongated and the sucker 

 openings are directed outward. These types of head are to be consid- 

 ered contraction states of the same species since intermediate stages are 

 present. The second type is found in Polypterus, and the first type in 

 Clarotes. The diameter of the scolex in specimens from Clarotes lati- 

 ceps ranges up to 1.72 mm, the diameter of a sucker of the same 0.250 

 mm. The diameter of the smallest scolex of this host is 0.75 mm. The 

 thickness of scolices from Polypterus endlicheri ranges from 0.67 to 1.28 

 mm., the breadth from 0.46 to 0.675 mm. No neck is present. The young- 

 est proglottids are thinner than the head and only slightly narrower. 

 Their breadth exceeds their length. Proglottids increase in both breadth 

 and length with age until they are quadrate in form or longer than 

 broad. The last proglottid is rounded posteriorly. The maximum 

 breadth of a proglottid from Clarotes is 1.5 mm, maximum length 2.0 

 mm. The maximum breadth of a segment from Polypterus is 1.5 mm. 

 and the maximum length of the same 1.9 mm. 



Sexual ripeness appears very early. The anlagen of genital organs 

 in stained specimens may be seen in very young proglottids within two 

 scolex lengths of the head. Many proglottids are sexually ripe before 

 becoming quadrate in form. The marginal genital pore alternates irreg- 

 ularly. Sometimes in as many as ten to twelve or more proglottids the 

 genital sinus may be on the same side tho this condition is rarely true 

 in more than five segments. The sinus (Fig. 176) is situated at about 

 the end of the first third of the segment. The vagina opens posterior to 

 the cirrus-pouch. The cirrus-sheath (Fig. 176) containing the coiled 

 cirrus (or cirrus plus the ductus ejaculatorius) has a pear-shaped form 

 and lies perpendicular to the margin of the proglottid. It may extend 

 14 across the breadth of the proglottid. The cirrus-pouch is about 0.20- 

 0.25 mm. long (measured from Klaptocz's figures which are drawn to 

 scale). The cirrus (Fig. 176) when protruded is very long and slender. 

 It is thicker at the base than at the point and is devoid of hooks or 

 bristles. The testes are elliptical, in number about 200. The testicular 



