NO. 1105. PROCEEDINGS OF THE NATIONAL MUSEUM. 169 



the vicinity of the female anl age farther than this it could not be 

 traced. The female organs gradually undergo a change, but this process 

 can not be described in detail because of lack of proper material. All 

 that it is at present safe to say is that a dark body of cells arises in the 

 vicinity of the receptaculum seminis and develops into the female glands 

 very similar to those found in the Bertia of the porcupine; the uterus 

 gradually extends over the segment suppressing the genital glands. 



Eggs globular with three membranes, but pyriform body not visible; 

 outer membrane 40 to 42 u in diameter; middle membrane could not be 

 studied; inner membrane immediately surrounding the oncosphere 21 

 JLI in diameter; hooks of oncosphere 9 ^ long. Numerous small calca- 

 reous corpuscles present in the parenchyma. 



This worm has an entirely different appearance from the one found in 

 the porcupine and it is possible that it will eventually be raised to 

 specific rank. My material, however, does not warrant such a step at 

 present. 



The following is proposed as a diagnosis of the variety: 



Diagnosis. Bertia americana leporis (Stiles, 1895), Stiles, 1896: 

 Strobila 23 to 47 mm. long by 5 to 6.5 mm. broad, possessing from 60 

 to 95 segments. Head about 0.6 mm. broad by 0.4 to 0.6 mm. long, 

 unarmed; suckers large, about 0.2 mm. in diameter, unarmed. Neck 

 absent, stobilization beginning immediately back of the head. Genital 

 pores alternate, situated in about the middle of the lateral margin. 

 Genital organs develop very early, the male organs being visible some- 

 times as early as the sixth segment. Cirrus large and ( ? ) smooth. 

 Cirrus pouch about 0.4 mm. long by 0.16 mm. broad ; its proximal por- 

 tion is very muscular and contains a vesicula seminalis. Vas deferens, 

 large and prominent, extends from the region of the female glands to the 

 cirrus pouch in the proximal portion of the segment ; testicles for the 

 greater part in the distal portion of the segment, about 50 in number, 

 arranged in an irregular row across the median field. Female glands 

 first appear in the eighth to fourteenth segment alternately right and 

 left of the median line; uterus spreads from female glands and occupies 

 entire median field ; ova globular with three thin membranes; pyriform 

 body apparently not present; outer membrane 40 to 42 }JL in diameter; 

 middle membrane?; inner membrane 21 /* in diameter; hooks of onco- 

 sphere 9 f.i long. Calcareous corpuscles present. 



Host. Lepus, sp. ?, by Curtice, development unknown. 



Types. Description based upon five specimens, of which Bureau of 

 Animal Industry Cestode Series No. 1171 is designated as Type and 

 deposited in the United States National Museum; paratypes Nos. 1170, 

 1172, 1175, 1176 U.S.N.M. 



Original material poorly preserved, alcohol ( ?) method, stained with 

 ha3inatoxylin. 



Geographical distribution. United States of North America (State?) 

 by Curtice. 



