236 ENTOZOA. 



General and Specific Characters. — A cestode helminth, considerably exceeding the 

 previously described species, both as regards length, breadth, and the thickness 

 of its individual segments ; the head also somewhat larger, abruptly truncated at the 

 crown, destitute of a rostellum, and consequently, also, of an hook-apparatus ; furnished 

 with conspicuously large sucking-disks, which are usually surrounded by a great quan- 

 tity of dark pigment granules, imparting to the head a blackish appearance ; the sexuaUy- 

 mature joints characterized by the possession of a more comphcated uterine organ than 

 even that of Tisnia solium, presenting nearly double the number of lateral branches, 

 which do not, moreoTer, branch out so dendritically as those of the so-called common 

 tapeworm, being also more closely packed and running outwardly in an almost parallel 

 manner ; as in T. solium, the first sexually-mature proglottis occurs somewhere about 

 the 450th joint, but whereas, in the former species, only some 200 subsequent segments 

 share this perfect character, in T. mediocanellata, on the other hand, there may be 

 present as many as 360 or even 400 mature joints (Leuckart) ; the reproductive papilla 

 occurs considerably below the centre of the lateral margin ; the joints are singularly 

 liable to form monstrosities, these abnormaUties sometimes affecting the reproduc- 

 tive organs, which become doubled or even trebled. 



The establishment of this species as distinct from T. solium is 

 unquestionably due to Kiichenmeister ; but it is not a little curious 

 to observe how accurately this determination was foreshadowed by 

 that shrewd naturalist and theologian, J. A. B. Goeze, who, in his 

 " Versuch einer Naturgeschichte der Bingeweidewiirmer thierischer 

 Korper," clearly indicates two forms of the common tapeworm, re- 

 marking (s. 278) : — " Die erste ist .die bekannte grosse, mit langen 

 dicken und gemasteten Ghedern, die ich Tcenia cucurbitina, grandis, 

 saginata, nennen will." The same author (s. 245), it will be remem- 

 bered, also pointed out the resemblance subsisting between the 

 tapeworm of the cat {T. crassicollis) and the vesicles (" Krystall- 

 blasen") and their contained "erbsformige Blasen" {Gysticercus 

 fasciolaris) of the mouse. In this way it was that the celebrated 

 pastor of St. Blasius, in Quedlinburg, almost contemporaneously 

 with the equally-distinguished zoologist Pallas, thus early arrived 

 at the conclusion that the hydatid-measles were a kind of tape- 

 worm. 



It is scarcely necessary for me to indicate more minutely the 

 distinctive peculiarities which distinguish this species from the com- 

 mon Tcenia solium, for although they are, indubitably, very well 

 marked, I do not think them sufficient to warrant the formation 

 of a new genus for the reception of this species. Thinking other- 



