116 T. H. JOHNSTON. 



University, for sending me some segments which he had 

 collected in this State from a similar host. 



Reference to Plate IV. 

 Ap.m. apical muscle plug; b.m. basement membrane; c. cortex; 

 ci. cirrus; c.s. cirrus sac; cu. cuticle; d.v. dorsal excretory vessel; 

 g. anterior end; k. posterior end ; l.m longitudinal muscle bundle; 

 m. medulla; n. longitudinal nerve; od. oviduct; ov. ovary; r. 

 rostellum; s. sucker; sc. subcuticular cells ; s.g. shell gland; t. 

 testes; tr.m. transverse muscle fibres; tr. v. transverse excretory 

 vessel; ut. uterus; vag. vagina; v.d. vas deferens; v.eff. vasefferens; 

 v.g. receptaculum seminis; v v. ventral excretory vessel;, x. neck; 

 z. septum between segments. 



Fi<*. 1. Scolex of Acanthotaenia tidswelli. Jnstn. 

 „ 2. Young segments showing excretory system and rudiments 



of genitalia. 

 „ 3. Sexually mature segment (considerably flattened). 

 „ 4. Transverse section of a segment, cut in front of the ovary 



and behind the vas deferens. 

 ,, 5. Cirrus sac. (Slightly diagrammatic). 

 „ 6. Female genital complex in part (diagrammatic). 



Figs. 1-4 were drawn with the aid of a camera lucida. In fig. 

 6, the common oviduct is not shown, its position being just below 

 the vagina. The vitellaria are not indicated in figs. 3 and 4. 



