478 ATONIC! DISEASES. 



common to man and the dog. The others are not readily distin- 

 guished from these two, and all are now said to be developed from 

 the hydatid forms found in the livers of sheep, rabbits, &c. The 

 peculiarity in the bothriocephalus consists in the shape of the head 

 (see Jig. 4), which has two lateral longitudinal grooves (bothria), 

 while that of the true taenia is hemispherical. The following is a 

 description according to Professor Owen : — " The Tmnia solium 

 attains the length of several feet, extending sometimes from the 

 mouth to the anus. The breadth varies from one-fourth of a line 

 at its anterior part to three or four lines towards the posterior part 

 of the body, which then again diminishes. The head (fig. 3, a) is 

 small, and generally hemispherical, broader than long, and often 

 as if truncated anteriorly ; the four mouths, or oscula, are situated 

 on the anterior surface, and surround the central rostellum, which 

 is very short, terminated by a minute apical papilla, and surrounded 

 by a double circle of small recurved hooks. The segments of the 

 neck, or anterior part of the body, are represented by transverse 

 rugae, the marginal angles of which scarcely project beyond 

 the lateral line ; the succeeding segments are subquadrate, their 

 length scarcely exceeding their breadth ; they then become 

 sensibly longer, narrower anteriorly, thicker and broader at the 

 posterior margin, which slightly overlaps the succeeding joint. 

 The last series of segments are sometimes twice or three times 

 as long as they are broad. The generative orifices (b b) are placed 

 near the middle of one of the margins of each joint, and are gener- 

 ally alternate (fig. 5 , c d). The Tmnia solium is androgynous ; that 

 is to say, it produces its ova without the necessity for the contact 

 of two individuals, the male and female organs being contained in 

 each." Professor Owen thus describes them : " In each joint of 

 this worm there is a large branched ovarium (Jig. 5, i), from which 

 a duct (h) is continued to the lateral opening ; the ova are crowded 



