102 L. Stieda on the Tsenise. 



there is frequently a Tapeworm of considerable size, which, ac- 

 cording to the character given by Dujardin* with especial refer- 

 ence to the habitat, I must regard as the Taenia omphalodes, 

 Hermann. 



This Taenia is 120-160 mill, in length; the head is quadran- 

 gular, measures l - 5-2*5 mill., and is distinctly separated from 

 the body of the Tapeworm ; it possesses neither a proboscis nor 

 a circlet of hooks, but only four round sucking-disks, 035 mill, 

 in diameter. The so-called neck, on which no joints are per- 

 ceived, even by the microscope, is l'5-2 - 5 mill, in length, and 

 1 mill, in breadth. The succeeding, distinctly recognizable 

 joints increase rapidly in breadth, so that at a distance of 

 25-35 mill, from the head the joints are already 4-5 mill, broad. 

 The joints do not, however, maintain this breadth, but diminish 

 in the lowest part of the worm to 3 mill. The length of the 

 joints increases very gradually, but constantly; the broadest 

 joints are ^-1 mill, in length, so that they are about five times 

 as broad as long; the last joints are about 2 mill, in length. 

 In consequence of this shortness of the joints, the Tapeworm, in 

 its upper parts, has a very finely striated appearance, whilst it 

 is only in the lower parts that, as the joints become longer, the 

 notched form more or less peculiar to the Tapeworms in general 

 manifests itself. The sexual orifices do not occur always upon 

 the same side, but, in irregular sections, sometimes on one and 

 sometimes on the other side. The number of joints forming the 

 Tapeworm may be ascertained to be 250-300 by direct count- 

 ing, which must be effected, on the parts nearest to the head, by 

 means of the microscope. A perfectly developed uterus, with 

 distinctly recognizable ova, is exhibited by the first joints of the 

 third hundred; fully developed embryos occur about twenty-five 

 joints further on. 



In the 40-50 joints lying nearest to the head no development 

 of sexual organs can be recognized, but in the part of each joint 

 in which the sexual organs are to be produced there is a greater 

 accumulation of cells. This becomes gradually differentiated in 

 this way : — a rounded mass, from which the female germ-pre- 

 paring organs are developed, becomes marked off in the middle 

 line of the joint, on the one side from a mass situated on the 

 lateral margin of the joint, and destined to produce the testes, 

 and on the other from a small elongated mass of cells deposited 

 on the opposite margin of the joint, and which serves for the 

 development of the germiducal organs. 



In the following joints (40-80), which increase chiefly in 

 breadth, the testes are first of all developed. From the mass 

 which is situated on the side opposite to the genital pore a large 

 * Hist. Nat. des Helminthes, p. 578. 



