161 



SCLEEOSTOMA HYPOSTOMTJM, Dujardin. 



Plate XXIII. 



Description. — Male, IG">™ ; female, 24"™. Body white, cylindrical, andstont. Head, 

 globular, a little veiitrally curved and trunoateat the mouth; head iiapillaj six; 

 neck papilla} not observed ; ventral cleft about opposite the end of the second fifth 

 of the oesophagus, counting from the head. Uuicellulai glands and lateral linos very 

 conspicuous. Mouth-opening round, obliquely inclined ; surrounded by a single 

 circle of very minute saw-lilie teeth. The globular ohitinous capsule is marked by 

 numerous longitudinal elevations, which are stronger at its bottom. The posterior 

 opening is circular, unarmed, but roughened. Around the moutti is a circular canal 

 which empties into a dorsal canal. There is apparently no pharyngeal apparatus as 

 in Dochmiiis. QJsophagus slightly swollen caudally. Two lateral ducts opening near 

 the mouth and situated on either side of the head are apparent; they seem to end 

 caudally in the lateral canals. Male about two-thirds the leugth of the female. 

 Bursa shallow, set on obliquely, oampanulate. Ventral costio either separate or 

 slightly so ; lateral slightly separate if at all ; dorsal pair irregular and widely sep- 

 arate; the dorso-lateral and dorsal forms a single stem with three lateral branches. 

 Spicula 1.5™™ long, linear aculeate, cross-striated, and bordered by narrow margins 

 whicli roll in towards each other. Two anal papillae. Female stout and thick, and 

 usually with a brown crust near the vulva. Vulva very near the tail. Tail full to 

 near the eud, but ending in an acute mucronate point. Uteri directed toward the 

 head; one, the caudal, makes a loop at the tail. The ovaries show loops near the 

 tail. Eggs elliptical, 0.1"°™ long, 0.06"'™ broad, laid in the gastrula stage. Embryo 

 not observed. 



Occurrence. — Sclerostoma liypostomuni is found iu tbe large intestine 

 of ruminants. It is present associated with (Esophagostoma Golum- 

 bianum iu sheep iu this country, but not abundantly. It is closely re- 

 lated to Sclerostoma equinum of horses, a species said to make tumors 

 in the intestines. As S. liypostomuni is rare, it has not yet been deter- 

 mined whether it causes intestinal tumors in sheep. Since 8. tetracan- 

 thum, whose embryos make tumors in the caBcnm of the horse, is more 

 nearly related generically to (Esofliagostoma than to Sclerostoma, I ain 

 inclined to believe, as I have proven in regard to (Esophagostoma Colum- 

 bianum in sheep, that the species belonging to the genus Q^jsophagostoma 

 are intestinal — tumor-making parasites rather than those of Scleros- 

 toma.. 



Life history.— M. Baillet {Nouveau Diet, de Med. T. VIII, art. Eel- 

 wiiw^/tes, 1886) is qutliority for the foUortiug: 



The sclerostome of ruiniuants is reproduced iu the same way as that of solipeds. 

 Its eggs, of which the vitcUus is segmented iu the uterus of tlie female, arts laid in 

 the large intestine and carried witiioutby the fecal material. TLey are hatched .after 

 23038 A P^ 11 



