430 DR. F. E. BEDDARD ON 



authors is to be referred. Yon Linstow himself assigns the worm 

 to the genus Davainea by reason of the form of the hooks. That 

 character, however, is now known in other genera — though all of 

 them of the family Davaineiclse. 



Those who have written subsequently upon this species, Da- 

 vainea struthionis, have probably accepted its generic rank rather 

 from the remarks of Max Braun than from the facts detailed in 

 V. Linstow's memoir. The former has pointed out in Broun's 

 ' Thier-Reich ' * that the alleged ovai-y of v. Linstow, consisting of 

 a number of separate spherical masses, is not indeed the ovary, 

 but an instance — largely met with in the genus Davainea — 

 of the " Parenchymkapseln " of German writers, in which the 

 ripe ova are massed after the disappearance of the uterus (when 

 that sac is clearly developed in the genus, which would seem to 

 be not always). Apart from this interpretation of the " ovary " 

 of v. Linstow and the nature and distribution of the sette 

 according to v. Linstow, there is nothing in the description of 

 that writer which would justify the reference of " Tcenia struthi- 

 onis " to the genus Davainea. It will be observed that there is 

 therefore no reason to distinguish this worm from Chapmaoiia 

 tauricoUis, at any rate so far. The detached masses of ripe ova 

 correspond with what I shall shortly describe in that species, 

 where the uterus is more or less broken up into partly separate 

 cavities containing eggs. The general form and size of the species 

 which has been termed Davainea struthionis, as figured by Paronaf, 

 is precisely what I have found to characterise the worm from 

 Hhea americana, which in other ways agi-ees positively with the 

 descriptions extant of Cha^miania tauricoUis. We have, how- 

 ever, to assvime, if this identification be correct, that v. Linstow 

 has missed the paruterine organ. This is, however, not evident 

 in immature proglottids. I can hardly claim to have proved 

 specific identity; but I believe it would be difficult on the 

 facts known to deny generic identity between these two species. 



In the meantime, however, I identify the species described in 

 the present paper with that described by Chapman, Fuhrmann, 

 and others as Tcenia, Davainea, or Ghapmania tauricoUis. It 

 reaches a length of fourteen inches or so and has thus much the 

 dimensions given by Chapman %. It is held that Tcenia argentina 

 of Zschokke § is the same species. If so, there would appear to 

 be a discrepancy in that the measurement of length given by 

 Zschokke is 8-9 cm. I am able, however, to clear up this diffi- 

 culty. The majority of my specimens agreed with Chapman's in 

 their dimensions ; but in a few the length was not greater than 

 8 cm. or so. 



The anterior segments of the body form a long tract, which 

 is very slender and widens out more or less suddenly to the wider 



* Bd. vi. pt. ii. p. 1446. 



t Ann. Mus. Civ. Geneva (2 a), ii. 1885. 



X Proc. Acad. Sci. Philadelpliia, 1876, p. 14. 



§ Ceutralbl. f. Bakt. u. Paras, iii. 1888, p. 2. 



