ox TWO xj:',v tapeworms. 695 



32, On Two new Species oE Cestodes belongino- respectively 

 to the Genem Lhistou'ia and Cotuania. By Fkank E. 

 Beddard, M.A., D.Sc. (Oxon.), F.R.S., F.Z.S. 



[Received June 5, 1916 : Read November 7, 1916.] 

 (Text-figures 1-4,) 



Index. 



Ststematic : — Page 



Xjinstowia lenmri-i, sp. n 695 



Cotuffnia margareta, sp. n 700 



I. Desc7~iption o/'Liustowia leimtris, .s'/j. n. 



Sexual Tapeworms from Lemurs being but little known, I was 

 specially interested to obtain from the small gut of an example 

 of the Slow Lemur {N'ycticelm.s tardigradus) two complete 

 specimens of a Cestode, besides a large fragment which was 

 found to belong to the same species. 1 refer this new worm to 

 the genus Llnstowia — at any rate, for the present, — giving i"easons 

 later aiter a due consideration of its anatomy. 



The worms ai-e about three inches in length, the varying 

 contraction rendering it impossible to give an accui-ate measui-e- 

 ment in either case. Tlie greatest diameter is 4 mm. The 

 scolex is almost spherical in form and of some size (1 mm.) ; it is 

 succeeded by a, short neck, where no strobilisation is visible. 

 The scolex is quite unarmed as to the suckers, and there is no 

 rostellum at all. The suchers are closely grouped on the anterior 

 face of the scolex, and not in the least lateral in position. The 

 only other external character of systema.tic importance, the 

 position of the generative orifices, was not appai-ent until the 

 worm was investigated by sections. They alternate from .side 

 to side, being uiainly nmssed upon one side, as many as ten being 

 sometimes successively upon the same side of the body. There 

 is thus nothing distinctive as to the systematic position of the 

 worm to be gained by an examination of the external characters 

 only, as is nearly always the case with Cestodes — a very few can 

 be identified without recourse to anatomical study. 



In transverse sections the c'07-tex is seen to be of a.bout the 

 same diameter as the medulla. The longitudinal muscles have a 

 charactej'istic arrangement which is in one way peculiar. In 

 addition to transverse fibres which bound the longitudinal layer 

 internally, a,s in most other Cestodes, the present species shows 

 similar fibres between the innermost of the longitudinal fibres 

 themselves, an arrangement which is, of course, well known 

 as characteristic of the Acoleidpe and of the genus Cotugnia 

 among the Da.vaineidte (see p. 700). This transverse layer be- 

 tween the inner and outer layers of the longitudinal sheet 

 consists of single delicate fibres, which are, however, quite 



