146 



ity aud indigestion. They are caused by the irritations set up in the 

 intestines by the worms. It is' found as a rule tliat a weakly sheep is 

 attacked by more than one species of parasite at a time, aud, conse- 

 quently, it is difl&cult to learn the symptoms produced by either of them 

 acting alone. Then, too, it should be remembered that symptoms are 

 sometimes incorrectly attributed to parasites when they really result 

 from diseases due to entirely different causes. Even the fattest sheep 

 harbor a few parasites, and some of them many more than one would 

 suspect from their apparent good health. 



The treatment should be directed toward keeping animals in good 

 health and in preventing them from acquiring parasites by providing 

 them with ])ure water and pastures which are not overstocked. Aledic- 

 inal treatment will rarely be attempted for any single species of these 

 parasites. A remedy which would prove effective for any one of them 

 would d for all. Their treatment will therefore be embraced under 

 that for Dochmius cernuus. 



Steongylus filicollis, Eud. 



Plate XIX. 



Description. — Male, 8 to 15™" ; female, 16 to 24™™. Body very small ; cephalic end 

 thread-like and tortuous ; caudal end, especially of female, thick and straight. Skin 

 marked by longitudinal lines standing at about equal distances apart. Head very 

 small, subspherical, continuous, with a swollen cylindrical neck; the length of the 

 inflated portion is about one- fourth that of the CESophagus. Four head papillse visi- 

 ble; the lateral papillae are probably present, but can not easily be made ont. Mouth 

 terminal; apparently witUout chitiuous armature. CEesophagus linear spatulate ; 

 unicellular gland ducts present. Position of ventral cleft not determined. 



Male: Filiform and uniform in size tliroughout its length; bursa strongly bilobed ; 

 the membrane beiug well filled on the dorsum but absent on the ventrnm ; can not 

 be spread without tearing ; costse generally symmetrically arranged, ventral slightly 

 separated ; ventro-lateral either joiued to lateral or ventral ; lateral scarcely sepa- 

 rated; dorsolateral joined to the dorsal, dorsal notched and with the dorso-latersil 

 form a stem, the two pairs uniting to form the dorsal stem ; the lateral cost» are the 

 longest. Spicula 1.5""" long, cylindrical, very slender and dark colored ; their 

 points are tipped with an oval inflatiou of the membraue and are more or less firmly 

 attached. 



Female: Tail obtuse; vulva situated about one-third of the entire length of the 

 worm from the tail ; body of the egg-bearing female enlarged in front of the vulva 

 by the swollen and crowded uterus. Uteri directed each way from the vagina, and 

 filled with comparatively few and large eggs in all stages of segmentation. Eggs 

 0.17™™ long, 0.08™™ wide, ovoid ; laid in the morula orgastrula stages. Embryo not 

 observed. 



This species occurs with Strongylus ventricosus in the upper end of 

 the small intestine of sheep and lambs. It is often mistaken for the 

 young of other species, and has beeti identified as a variety of Strongylus 

 contortus. It is needless to observe that it is specifically different from 

 any other nematode found in sheep ; a glance at the plate illustrating 

 the species is suflicieat proof of this, It is quite abundant during fall 



