A NEW SPECIES OF AVIAN TAPE- WORM. 159 



laid on the egg-mass either generically or specifically, because, 

 although in the case of Liga the length (3 mm.) and number 

 of segments (16) bring it into line with mine and Pagenstecher's- 

 specimens, yet in other essentials the generic characteristics are 

 totally different, and this difference excludes it from the genus 

 Hymenolepis ; and these remarks also apply to Anomotaenia 

 (I'aeiiia) constricta. 



The question of the greater proportional length, and conse- 

 quently the increase in the number of segments, raises a doubt 

 in my mind as to the claim for Pagenstecher's specimen of being 

 specifically the same as Creplin's microsoma. This disparity in 

 the length of the strobila, the number, length and breadth of the 

 segments composing it, of those specimens of microsoma in the 

 Pfaff-Olrik collection and those Krabbe found ; also their sexual 

 development apart from the egg-masses in the 500-segmented 

 worms, is convincing proof to me that, although the cephalie 

 hooks as figured by Krabbe, more especially Fig. 4c, are in 

 agreement with mine, Fig. 4e, they are specifically distinct. The 

 doubt of Pagenstecher as to his worm being Creplin's microsoma 

 in the absence of the hooks in the latter is quite admissible, 

 and I am convinced that, although the strobila of his worm was 

 shorter and contained fewer segments than mine, the developed 

 hermaphrodite condition of the genitalia in the strobila, alsa 

 the form of the egg-masses both in the last segments and 

 in separated free proglottides in the intestine, point to them as 

 being identical. On this divergence in the form of the strobila, 

 and on a comparison of the development of the sexual organs in 

 the same and subsequent uterine mass, I base the conclusion 

 that neither my specimen nor that of Pagenstecher's is identical 

 with Creplin's, Pfaff and Olrik's, or those specimens known by 

 Krabbe himself as Taeiiia microsoma. Generically, Hymenolepis, 

 both my specimen and that of Pagenstecher, will remain the 

 same ; but the specific name, microsoma, of Pagenstecher will be 

 deleted, and, together with mine, will, from the similarity of 

 the character of the uterine sac to the Greek small v, receive 

 the specific name of upsilon. 



The dualism of the ovarian uterine sac to which I have 

 above called attention is, as far as I know, a unique 

 character, it being possessed by no other avian tape- worm ; 

 yet I think that it is not of sulficient importance for the form- 



