118 The Common Liver Entozoon of Cattle. 



the animal seldom attains the length' of an inch, this drawing 

 (fig. 1) represents an ordinary specimen magnified about six 

 diameters linear. To the naked eye the skin appears smooth, 

 hut microscopic aid shows the cuticle to be furnished with 

 numerous rows of minute pointed spines (fig. 5). In the 

 Amphistome we find two pores, one at either extremity of the 

 body; but in the genus Fasciola, as also obtains in the majority 

 of flukes, the oral and ventral suckers are more nearly approxi- 

 mated. The latter pore is frequently termed the acetabulum, 

 and in the illustration before us it is seen occupying a median 

 position at the base of the neck. It does not communicate with 

 any cavities internally, and is simply employed as a " holdfast." 

 The oral sucker forming the mouth leads to the short oesophagus, 

 which very soon divides into two primary stomachal or intes- 

 tinal trunks, which latter in their turn give off branches and 

 branchlets ; the whole together forming that beautiful dendritic 

 system of vessels which has often been compared to foliar 

 venation. This remarkably formed digestive apparatus is 

 accurately represented in the annexed diagram (fig. 2), which 

 should be contrasted with the somewhat similarly racemose 

 character of the water- vascular system, shown on the opposite 

 side of the plate (fig. 3). Let it be expressly noted, however, 

 that in the digestive system the majority of the tubes branch 

 out in a direction obliquely downwards, whereas those of the 

 vascular system slope obliquely upwards. A further compa- 

 rison of the disposition of these two systems of structure with 

 the same systems figured and described as characteristic of the 

 Amphistome, will at once serve to demonstrate the important 

 differences which subsist between the several members of the 

 two genera. 



These distinctions stand out with equal cogency if we care- 

 fully examine the arrangements of the complicated reproductive 

 apparatus; and here again the colours introduced into the 

 plate at once enable us to institute a new comparison, and at 

 the same time supersede the necessity of an otherwise extended 

 description of the parts. All the orange-yellow-brown masses, 

 with their delicate, connecting, dark coloured lines belong to 

 the female division of the reproductive elements of this her- 

 maphroditic species ; the dark, central mass of folded tubes 

 being the combined uterine cavity and oviduct, in which the 

 eggs complete their final stage of development, before they 

 gain access to the outer world. The multitude of little bo- 

 tryoidal organs occupying the sides of the body, and all that 

 part which may legitimately be called the tail, are the so-called 

 yelk-forming glands, and it will be observed that they commu- 

 nicate with the above mentioned oviducal, uterine folds, by the 

 intervention of two common ducts, which run transversely in- 



