DEFINITION OF T^ENIA MADAGASCARIENSIS. 663 



been able to find. Indeed, I am almost inclined to think that 

 Weinland has been misled by the coagulation of the not unfrequently 

 granular mass, lying between the widely separated inner and outer 

 shells. The embryo measures almost 0'03 mm., and after the applica- 

 tion of alkalis distinctly exhibits its six hooks (O'OIT mm. in length). 



Among the segments which I examined there was one which, even 

 on cursory observation, attracted attention by its pale appearance 

 and small size, and especially by its narrowness. On microscopic 

 examination it proved to be without eggs, and had apparently, from 

 some unknown cause, never formed any. The receptaculum, with its 

 efferent canal, was more distinct than in the fertile proglottides, and 

 also of a larger size, unquestionably because the material had not 

 been expended otherwise. If I remember aright, the friendly donor 

 himself called my attention to this joint, with the remark that he 

 had repeatedly observed similar sterile proglottides in his Tcenia fiavo- 

 punctata.'*- 



The calcareous corpuscles are in this species also small and scanty. 



GROUP B. As in Hymenolepis, the sexual apertures are unilateral, 

 and the eggs provided with two smooth envelopes, and, instead of being 

 isolated, enclosed in a group within a firm enveloping substance, which is 

 continued exteriorly by a felt-like fibrous tissue. Head ? 



Subgenus ? 



Taenia Madagascariensis, Davaine. 



Davaine, " Notesur une nouvelle espece de t&iia, recueillie a Mayotte," Archives de 

 m6dedne navale, t. xiii., 1870. 



Davaine, "Traite des Entozoaires," second edition, p. 922 ; or Mem. Soc. biol., 1870. 



A Tasnia of probably about 8 cm. in length, and with about 100 

 somewhat broad joints, which are at first short, but gradually assume an 

 almost square form, measuring in length and toeadth about 2*6 mm. 

 In the interior of these joints there are a large number of small bodies of 

 oval form (0*9 mm. long and 0'6 mm. broad), which are arranged in 

 transverse rows, alternating with each other, but without touching at any 

 point. Their number in each proglottis amounts to from 1 2 to 1 5 0. These 

 are not eggs, as might have been supposed, but balls of eggs, covered exter- 

 nally by a spongy substance of somewhat considerable thickness, in the 

 form of a clear sphere (of 0*5 or 0*3 mm.). The eggs themselves always 

 measure 0'04 mm. (the inner egg-shell 0'02, and the embryo 0'015 mm.), 

 and the number found in each ball is about 300 to 400. In favourable 



In two communications which have appeared since these words were written (Nova 

 A eta A cad. Cas. Leop. -Carol., loc. cit.) Weinland has himself described this abnormality. 

 Similar sterile joints are occasionally found in other tape-worms. 



