r)22 



identity is assumed from their similarity. Plana was ac- 

 quainted with Megniu's i>:ii.fi-, ))Ut separated his form from 

 Meg-nin's species chiefly nn account of the form of the hooks 

 on the suckers, the number of hooks on the rostellum, and the 

 arrang-ement of the genital pores. Krabbe (1882, pp. 361-364, 

 Tab. II, figs. 5.')-60) published as Taenia tetragona Molin, some 

 cestodes whicih Fedschenko had found in chickens in Turke- 

 stan. He admits the total inadequacy of Molin's figures and 

 descriptions, but determines his specimens as T. tetragona on 

 account of the egg capsules. The characters given are as fol- 

 lows: 



Length to 250>iini, breadth, 1.6mn'; posterior segments, 1.2mm 

 long by 1.6mm broad. Head provided with a short and broad 

 retractile rostellum, surrounded by about 200 hooks arranged 

 in a double row; hooks measured 6 /" long from the apex of 

 the prong to the end of the dorsal root; ventral root 11 fi long; 

 suckers surrounded by several rows of similar instable hooks 

 of different form from those of T. australis. Genital pores 

 unilateral; cirrus smooth, 21 a long by 8 /i thick. Eggs ar- 

 ranged in egs sacs, 10-12 ova in a group, 40 to ca. 90 groups in 

 a segment. 



Since Krabbe's paper authors have as a rule accepted T. tet- 

 ragona as a good species. Blanchard (1891B, pp. 433, 436) rec- 

 ognized D. echinoibothrida as a distinct species; recognized D. 

 tetragona (Molin) as valid, and made T. bothrioplitis a syn- 

 onym of D. tetragona. Grassi & Rovelli (1892, p. 84) claiim to 

 have recognized both T. tetragona Molin and T. bothrioplitis 

 Piana, and state that they have found both forms; T. echino- 

 bothrida Megnin they did not find, but they think it is possi- 

 bly identical with T. bothrioplitis Piana. Railliet (1S93, pp. 306- 

 307) has followed Blanchard (1891). 



Fromi the above it is questionable whether Molin's specific 

 name teti"agona can be retained, unless the originals can be 

 found and redescribed, for the description given by Molin is 

 unrecognizable without the types. It might possibly be re- 

 tained upon the ground that it is impossible to show that T, 

 tetragona of present authors is not identical with T. tetragona 

 Molin. I refrain temporarily from suppressing the name, as 

 I hope the types may be re-examined. Krabbe's description of 

 T. tetragona can hardly be taken into consideration in this 

 question, as there is nothing to show that his specimens are 

 identical with Molin's forms, and asi Krabbe himself admits the 

 uselessness of Molin's description and figures. The differences 

 between the species described by these three authors- (Megnin. 



