THE LARGE ROUND WORM. 



ASCAKIS LUMBEICOIDES, Linn. 

 Plate XXI. 



Description. — Male aad female 1.50"'" eacli ; la the specimens figured 120 each. Body 

 very large and thick, obtuse at each ead, of a yellowish color, skin marked by rings. 

 The site of the vulva is marked by a smooth wide baud about one-third the entire 

 length from the head. There are three longitudinal bands ; the two wider are nearly 

 lateral ; the third is ventral. The head end is abruptly terminated in three well- 

 formed lips ; the dorsal possesses two papilbe near its base and the two ventral one 

 each. Each lip consists of a obitinous support covered by outioular membrane. The 

 tail of each is obtuse. The description after Solineider {Monographie d. Nematoden, 

 p. 36) is as follows : 



"Lips nearly equal, their form changing from semi-circular to quadrangular. Teeth 

 very fine. The lobes undivided. The azygos lobe has a rounded point, and reaches 

 with its anterior end to the front of the saddle. Cu ticular rings longitudinally ri bbed , 

 Vulva 40 to GJ"""" from the cephalic end. Vagina 11'""" long. Tail of the male flat ou 

 the ventral side. Only behind the anus is the skin broadened into a bursa; sixty-nine 

 to seventy-five papillse on each side ; the first seven pairs of these papillae stand behind 

 the anus; the second pair stand nearer the ventral line than the first and third; the 

 fourth and fifth pairs and the sixth and seventh pairs are united into double papillae. 

 (See Fig. 7.) The succeeding stand first in a single row, then in pairs forming a 

 double row ; and on the whole they are very irregular. An unpaired papillae stands 

 in front of the anus. Spicula two, each a single tube, with its point terminating 

 bluntly and irregularly in front. 



"This parasite occurs in the small intestine in man and swine, and sometimes 

 forces its way into the gall ducts, stomach, cesophagus, nose, and Inngs." 



In one flock of sbeep only has the author found this parasite. In this 

 flock it occurred in six animals, a majority of those examined. That it 

 is not a common parasite is attested by the writings of various Euro- 

 pean helminthologists. A few of the latter have described a special 

 species (Asearis ovis), from the sheep, but as it is infrequently found it 

 seems to be an inconstant parasite or an adventitious one, i. e., it is 

 probably a constant parasite of some other domesticated animal, and 

 occasioDally only becomes parasitic on sheep. Besides, the specimens 

 figured always seem to have been immature, and do not differ from 

 Asearis lumhricoides of the same size and age. 



In the single flock in which this worm was observed all the specimens 

 found were immature. The vegetative organs of these specimens differ 

 in no essential point from those of Asearis lumbrieoides as figured by 

 various authorities. In addition, a close comparison of these specimens 



151 



