TJEXIA ECHINOCOCCUS 249 



vitellogene gland narrow, triangular ; shell-gland globular ; uterus 

 with median trunk and fourteen to eighteen short ramified lateral 

 branches on either side. The oncospheres, which have shells, are 

 oval (0*039 '3 mm.) ; the shell is thick and radially striated. 



Of this species only two specimens have been recorded ; they 

 occurred in human beings and were sent at different times to the 

 first describer of them by a doctor in Lincoln (Nebr.). Perhaps 

 Tcenia solium, var. abietina, Weinld., which was found in a Chipe- 

 way Indian, is of the same species in spite of the shorter 



segments. 







LITERATURE. 



WARD, H. B. Rep. of the Zoologist. (Ann. rep. Nebraska State Board Agric. 



f., 1895-6, p. 257 ; ibid., f. 1896-7, p. 173.) 

 A New Hum. Tape-worm. (West. Med. Rev., 1896, i., p. 35 ; Proc. Nebr. 



State Med. f., 1896, p. 83.) 



Note on T. confusa. (Zoolog. Anzeiger, 1897, xx -> P- 3 21 -) 



GUYER, M. F. On the Struct, of T. confusa. (Zoolog. Jahrb., Part f. Syst., 

 1898, xi.) 



8. Tcenia echinococcus, v. Sieb.> 1853. 



Syn. : Tcenia nana, v. Ben., 1861 (nee. v. Sieb., 1853). Echinococcifer 

 echinococciis , Weinl., 1861. 



Tcenia echinococcus measures 2*5 to 5 or 6 mm. in length ; the 

 head is 0*3 mm. in breadth, and has a double row of twenty- 

 eight to fifty booklets on the rostellum. 



The size and form of these booklets vary (the larger ones are 

 0*040 0*045 mm. in length, the smaller ones are 0*030 0*038 

 mm. in length). The suckers measure 0*13 mm. in diameter ; the 

 neck is short ; there are only three or four segments, the posterior 

 segment being about 2 mm. in length and 0*6 mm. in breadth. 

 The genital pores alternate ; there are forty to fifty testicular 

 vesicles ; the vas deferens is spirally coiled ; the cirrus -pouch 

 is pyriform. The ovary is horseshoe-shaped with the concavity 

 directed backwards ; the vitellogene gland double, each half almost 

 bean-shaped, at right angles to the level of the segment ; the 

 shell-gland is round. The median trunk of the uterus is dilated 

 when filled with eggs and (instead of lateral branches) has lateral 

 protuberances. It is not unusual for the eggs to form local heaps. 

 The embryonal shell is moderately thin, with radiating fibres, 

 almost globular, 0*030 0*036 mm. in diameter. 



When mature this parasite lives in the small intestine of the 



