178 ILLINOIS BIOLOGICAL MONOGRAPHS [178 



closely the Taenia ambloplitis, noticed in the Rock Bass, Ambloplitcs rupestris 

 (Proa, 1887, 22,), and may be the same. Distinguishing it with the name of 

 Taenia leptosoma, its characters are as follows : Body long and thin, and at the 

 forepart thread-like. Head unarmed, without rostellum, with four equidistant 

 hemispherical bothria ; neck very short or none ; anterior segments transversely 

 linear, many times wider than long; posterior segments gradually becoming pro- 

 portionately longer and quadrate and barrel shaped ; genital apertures marginal, 

 alternating irregularly. Ova spherical. 



"Length from 6 to 9 and 26 inches, shortening to one half or less ; breadth to 

 2 and 2.5 mm. Head 0.25 to 0.5 mm. broad; bothria 0.125 to 0.175 mm - Anterior 

 segments an inch from the head 0.175 mm - l° n g by 1 mm. broad; posterior seg- 

 ments 0.5 to 0.75 mm. long by 2 to 2.5 mm. broad. Ova 0.028 to 0.032 mm. in 

 diameter. 



"A single slender Scolex associated with the longest Taenia was 4 mm. long 

 by 0.25 wide, but elongated to 8 mm. by 0.1 wide. The head was of the same form 

 as that of the Taenia. After being in alcohol, the head of the Scolex was 0.225 

 mm. wide, with the bothria 0.1 in diameter. The posterior part of the body ex- 

 hibited traces of segmentation, with the segments 0.075 mm - long by 0.25 wide." 



In November 1890 from the same host species Leidy reported Tae- 

 nia nematosoma. His description is quoted : 



"Taenia nematosoma, n. s. — Head rounded quadrate, unarmed, with equi- 

 distant hemispherical bothria and a small central papilla ; neck short or none ; 

 fore part of body linear; anterior segments much wider than long; posterior seg- 

 ments gradually becoming proportionately longer, quadrate or barrel-shaped ; geni- 

 tal apertures marginal and alternating irregularly. Length to 9 inches, contracting 

 to about one-half. Breadth of head 0.375 to 0.5 mm.; bothria 0.175 wide; neck 

 0.25 wide; anterior segment an inch from the head 0.175 mm. long by 2 mm. 

 broad ; posterior segments 0.75 mm. long by 2 mm. broad, and when contracted 

 widening to 2.5 mm. Ova spherical, 0.028 to 0.032 mm. 



"A half dozen specimens in the stomach of two Pickerel, Esox reticulatus." 



Neither report was accompanied by drawings. 



Leidy 's two forms agree in practically every particular as to 

 measurements and proportions and host species. The writer therefore 

 concludes that they are identical and includes them both under the 

 name P. nematosoma (Leidy). This species differs from P. ambloplitis 

 chiefly in the measurement of the suckers. Its measurements vary 

 greatly from those of P. pinguis and from P. esocis Schneider. None 

 of Leidy 's specimens remain, so the species must continue a species 

 inquirenda. Monticelli (1891) on account of the confusion of this 

 name with Taenia leptosoma Diesing suggested the name Taenia somato- 

 lepta. However the name nematosoma should be preferred because it 

 is an earlier available name than somatolepta. La Rue (1911:475) 

 made this one of his list of Proteocephalus species. 



