42 



BULLETIN 69, UNITED STATES NATIONAL MUSEUM. 



Genus DIORCHIS Clerc, 190S. 

 (For generic diagnosis see p. 98.) 



DIORCHIS ACUMINATA (Clerc, 1902) Clerc, 1903. 



Figs. .30-30. 



Drepanidotcenia acuminata Clerc, 1902a. p. f>59, figs. ?>. 4. 



Diorchis acuminata (Clerc, 1902) Clerc, 1903, pp. 24S, 249, 255. 281-284, pi. 



8, fig. 13 ; pi. 9, fig. 25 ; pi. 11, figs. 78, 79. 

 Diorchis accuminata Clerc, 1903, p. 249 (misprint for D. acuminata) . 

 Taenia acuminata Clekc, 1903, p. 283 

 Specimens of a tapeworm (from the collection of H. B. Ward, de- 

 posited in the U. S. National Museum Helminthological Collection, 



No. 7237) collected in Nebraska from Fulica 

 americana apparently belong to the species 

 Diorchis acuminata. 



External anatomy. 



These specimens measure 35 mm. in length 

 by 0.65 mm. in maximum breadth. The 

 final segments were not yet gravid, and it is 

 consequently evident that the full-grown 

 worm may be considerably larger than indi- 

 cated by the above figures. 



The head (figs. 30, 31) measures 160;u, in 

 length by 225 to 235/^ in width. The rostel- 

 lum is cylindrical when protruded, slightly 

 broader at the tip than at the base, measur- 

 ing 100/x in length by 50/x in diameter at the 

 base and 70ja in diameter at the tip. It is 

 armed with 10 hooks (fig. 32), with long 

 dorsal and short ventral root and measuring 

 38|U in length, the dorsal root being 25/x, and 

 the prong 13/x in length. The suckers are 

 about 80ju, in diameter and are armed with 

 minute spines less than 5ju, in length, set close 

 together in diagonal rows covering the entire 

 surface of the sucker- 

 Segmentation begins very close behind 

 the head, and in this region the strobila is of 

 about the same breadth as the head. The breadth then becomes re- 

 duced to about 150|Li and afterwards gradually increases throughout 

 the remainder of the strobila. The segments are broader than long, 

 the largest measuring 80/i in length by 650^ in width. 



I 1 



lOQir. 



Fig. 30. — DioKCHis acumi- 

 nata : Head and an- 

 terior portion or stro- 

 BILA. 



