Intestinal Parasites of the Dog. 315 



There is therefore abundant reason for the great prevalence of 

 the tape- worm before us, and especially in poor, neglected, dirty, 

 vermin-infested dogs. There is also the obvious resort in treat- 

 ment and prevention to the use not only of tseniacides for the de- 

 struction of the mature worm, but also of parasiticides for the 

 destruction of the vermin on the skin. 



Taenia Litterata. T. Pseudo-Cucumerina. T. Lineata. 

 T. Canis Lagopodis. T. Margaritifera. Mesocestoides 

 Litteratus. Lettered T. These have been held to be one 

 species and again divided into three separate ones. It has also 

 been questioned whether they do not belong rather to the 

 bothriocephali to which the absence of proboscis and booklets, 

 and the very restricted development of generative organs seem 

 to ally them. 



The Taenia Litterata has a globular head, slightly flattened 

 or bilobed, .9 mm. broad, without proboscis or hooks but with 

 four suckers each having a wide longitudinal slit. The neck is 

 long, at first narrowing insensibly and then slowly widening and 

 the first segments appear about an inch behind the head. The 

 anterior segments are distinctly narrowed in front and behind, 

 while the riper segments are in the main wider behind . The 

 genital pores are not lateral but are double, the vulva in front of 

 the male orifice, near the middle of the ventral surface. The 

 pyriform uterus, near the posterior border shines through the 

 transparent envelope giving the peculiar lettered appearance to 

 the segment. The mature worm is one to two or even five feet. 

 Eggs, very numerous, with thin transparent walls showing the 

 living embryo within, which retains its vitality in spite of freez- 

 ing or drying (Baillet). Ova 40 to 60 jw, by 35 to 43 /*. 



Habitat. Small intestine of the dog in Iceland and Europe. 

 The head is usually so firmly attached to the mucosa that it may 

 remain when the worm is pulled off. 



Larval form unknown. 



Bothriocephalus Latus. Broad B. Length 25 feet or 

 more, breadth aibout i inch at its greatest. Head -^ inch, ob- 

 long, club-shaped or lanceolate, flattened with two lateral pits 

 (bothridia) used as suckers, and devoid of booklets. First seg- 

 ments very short and narrow, enlarging very gradually ; in the 

 middle of the worm they are three times as broad as long, and 



