A NEW SPECIES OF TAPEWORM. 401 



ought the method of fructification, even though it be reversive 

 as in the present case, prevent the inclusion of a species in a 

 genus with whose characteristics it otherwise agrees. Especially 

 is this so when we consider that the enclosed vestibule leading: 

 to the vagina is expansive, the vagina itself is a narrow canal, 

 and the lumen wide and capacious, corresponding to the ana- 

 tomical features on which the genus Hymenolepis is founded. 

 The costals of the vestibule are not to be explained in the same 

 manner as B. H. Ransom does the ridges and rugae of the 

 cuticula of the vagina of H. megalops, Nitzsch (Studies from the 

 Zoo. Lab. University of Xebraska, U.S.A., 1892), for instead of 

 being circular they are vertical, thus forming a cone, and are 

 composed apparently of the same skeletal substance as are the 

 hooks on the rostellum. As this portion of the female genitalia 

 from its earliest inception is the most prominent and striking 

 part of the internal anatomy, and although it is in situ a vase- 

 shaped organ, still from a superficial observation with a ^-inch 

 objective, or even a ---inch, the observer would be struck by its 

 similarity in outline to a miniature hair-pin of the form shown 

 in Fig. 17. I propose the name Hymenolepis acicula sinuata, for 

 the specific portion of which I am indebted to C. W. Bell, Esq., 

 M.A., of King's School, Canterbury. 



Explanation of Plate 30. 



Fig. 1 . Scolex and neck. 

 ,, 2. Commencing formation of testes. 

 „ 3. Male segments. 

 ,, 4. Female segments. 

 ,, 5. Early formation of uterus. 

 „ 6. Uterine segments. 



,, 7. Segment with ova developing to hexacanth stage. 

 ,, 8. Six-hooked brood in segment. 



„ 9. The three terminative segments. The penultimate seg- 

 ment is barren. 

 Figs. 1-6 ventral, 7-9 dorsal, all x 50. 



Journ. Q. M. C, Series II.— No. 64. 30 



