T. B. ROSSETER ON HVMEXOLEPIS FARCIMINALIS. 309 



The study of the genitalia of H. farciminalis has led me to the 

 conclusion that it can no longer be retained in the heteromorphic 

 genus Taenia-, and as it possesses essentially the qualifications 

 formulated by R. Blanchard in 1891 in defining- the genus 

 J/f/menolepis, Weinland, even as regards the ovum possessing 

 three envelopes, therefore, although it has retained the generic 

 name of Taenia for the past one hundred and twenty-five years, 

 I have decided to remove it from that genus to the genus 

 ////menolepis, Weinland. 



Finally, I might point out a conclusive specific characteristic 

 other than the " farcimen " form of the segments. The recep- 

 taculum seminis of avian tape-worms is, as a rule, variable in 

 form and size. It may be pyriform, orbicular, or oval. Let us 

 again take Hymenolepis serpentalus, one of the Dicranotaenia, for 

 comparison. Contrast the gigantic sa men-blase of //. serpentuh's 

 and its aborted vaginal canal with the elongated, filiform, medio- 

 constricted somen blase of H. farciminalis, and its long, slender 

 vaginal canal, and it will readily be conceded that these characters 

 form convincing proof of the distinctness of the two species. 



Explanation of Plate 24. 



Fig. 1. Portions of strobila ; a, scolex, neck, and early segmenta- 

 tion, x 35 ; h, succeeding segments with commencing 

 formation of genitalia, x 18 ; c, mature hermaphroditic 

 segments, x 18; d, an inverted segment, as described 

 in text; d.u., dendritic uterus; l.m.a., long muscles 

 anterior; l.m.p., long muscle posterior, x 18; e, uter- 

 ine segments; u., uterus, x 18;/, terminal segments 

 with six-hooked brood, s.b., showing the transition 

 of the segments to Goeze's sausage or pudding forma- 

 tion, x 18. Fig. 1, (ja, segment showing further 

 evolution of proglottides, x 9 (from another specimen). 

 Fig. 1, gb, proglottis, x 9, from isolated segments 

 taken from intestine of jay, whose only internal para- 

 sites were H. farciminalis. They contained empty 

 six-hooked brood cases ; by this I assume they were 

 the final stage of the proglottis in the strobila. Fig. 1, 



