36 T. U. R0SSETER ON THE TAPE-WORMS 



The ovaries are the usual paired organs, situated distally and 

 proxinially ; the ovarian eggs are contained in semi-lunar pouches. 

 The yelk-gland is oval, and lies in the medio-posterior portion of 

 the segment. The yelk-gland I have been unable to trace, and 

 none of my specimens were sufficiently matured to have 

 developed uterine segments, or for the ova to have passed into 

 the hexacanth stage. 



Amongst my specimens was one in which the segments of the 

 strobila differed from the proglottides of the other specimens. In 

 this specimen (Plate 5, Figs. 1 — 3) the youngest or anterior 

 segments are claviform, and are devoid of rudimentary male 

 organs. These are evolved by growth into a parallelopiped 

 formation, in which the male organs are produced and perfected, 

 as also the " anlage " of the spinous vaginal pore, whilst the fol- 

 lowing mature hermaphroditic segments are campanulate. In 

 another type specimen (Fig. 4) the anterior segments, which I 

 infer closely follow the scolex and neck — if this is not the actual 

 neck — are three times as broad as long. These are followed by a 

 series of very beautiful infundibuliform proglottides (Figs. 5 — 7), 

 in which the testis, primarily, and the other male organs are 

 formed and perfected ; and these again are resolved into the 

 campanulate hermaphroditic segments, the terminative or pri- 

 mary segment being rounded at its base. It is rare, not only 

 in this but in other species of tape-worms, to find in the terminal 

 or primary segment the hermaphroditic genitalia perfected and 

 fecund. 



I consider that the specimen represented in Figs. 1 — 3 is an 

 abnormal one segmentally, and that Figs. 4 — 7 show the normal 

 specific specimen. But this abnormality of the proglottides does 

 not destroy its specific individuality, as the anatomy of its 

 generative organs is coincident in every respect with the genitalia 

 of the normal specimen. 



Hymenolepis nitidulans, Krabbe. 



Taenia nitidulans (Friis, 1869), Krabbe, 1882. 

 Hymenolepis nitidulans, Hosseter, 1906. 



Krabbe, in his Bidrag til Kundskab oin Fuglenes Baendelorme 

 (p. 7, no. 15, tab. 1, figs. 16, 17), says that Friis found 

 (August, 1869) this tape-worm parasitic in the intestine of Tringa 



