140 ILLINOIS BIOLOGICAL MONOGRAPHS [140 



pressed backward until the ends of the lobes touch in the median line. 

 In the investigations of the writer covering a large number of Proteoce- 

 phalidae he has been unable to find a fusion of the ovarian lobes. He 

 must conclude that Nufer's drawing of this condition is hardly trust- 

 worthy. Nufer also claims that the walls of the uterine pouches event- 

 ually degenerate so that the eggs come to lie in the parenchyma. There 

 is reason to doubt the accuracy of this statement. Many sections of a 

 large number of old ripe proglottids of P. macrocephalus and other 

 species of this genus have been examined by the writer who has failed 

 to find any such degeneration of the uterine walls. Nufer's material 

 must have been in extremely poor condition, or else he wofully misin- 

 terpreted the appearance of the sections. 



The foregoing discussion of Nufer's article leads to the conclusion 

 that the complete specimens taken by Nufer from Anguilla vulgaris 

 were probably P. macrocephalus, as he identified them. One must fur- 

 ther conclude that a part of his description was based on the two loose 

 end-proglottids which really belonged to P. fallax and that these were 

 ingested with the food of the eel or that they were accidentally put 

 with the cestodes of Anguilla during Nufer's manipulation of the speci- 

 mens. It also seems that the eggs which Nufer measured came from 

 P. macrocephalus. Liihe (1909) gave a very short diagnosis of this 

 form but included no figures of it. La Rue (1911:475) included this 

 form in a list of Proteocephalus species and stated that Taenia dilatata 

 was a synonym of P. macrocephalus. 



Some specimens which have been identified by the writer as P. 

 macrocephalus were collected by Professor H. B. Ward in the course of 

 a biological investigation of Sebago Lake, Maine during the summer of 

 1907. This investigation was conducted under the auspices of the 

 United States Fish Commission. Professor Ward examined 11 speci- 

 mens of Anguilla chrysypa Raf. Of this number five had no cestode 

 infection whatever; two yielded two Proteocephalids each; one yielded 

 one Proteocephalid, and two others together yielded eighteen cestodes 

 and some pieces. Of these eighteen cestodes eight were Proteocephalids. 

 Some of the pieces also belonged to this group. Altogether then there 

 were thirteen Proteocephalids plus some pieces but there was no com- 

 plete strobila among them. The specimens described are from bottles 

 No. 47, 54, 56, 71 and 72 of the Sebago Lake collection. 



The worms are long and slender. No complete strobila was found 

 but a fragment from the middle region of a worm measured 120 mm. 

 long. The maximum breadth observed was 1.8 mm. Young proglottids 

 are much broader than long, measuring 0.33 mm. broad by 0.022 mm. 

 long. Mature proglottids are broader than long, measuring 1.0-1.20 



