EUSTRONGYLUS GIGAS 



323 



The males attain a length of 40 cm., and a diameter of 4 6 

 mm., the posterior extremity is transversely truncated; the anal 

 orifice is within the base of the collar-like bursa, the thickened 

 edges of which are beset with papillae ; the spicule measures 

 5 6 mm. in length. 



The females attain a length of 100 cm., and a breadth of 12 

 mm. The anus is crescent- 

 shaped and terminal. The 

 vulva is 50 70 mm. distant 

 from the anterior extremity. 

 The eggs are oval and have a 

 thick shell presenting numerous 

 depressions ; the shell itself 

 is brownish, but it Is colour- 

 less at the somewhat thick- 

 ened poles ; it measures 0*064 

 mm. in length by 0*04 mm. 

 in breadth. 



Eustrongylus gigas lives in 

 the pelvis of the kidney, more 

 rarely in the abdominal cavity 

 of the seal, otter, dog, wolf, 

 fox, horse, marten and pole- 

 cat, exceptionally also in 

 human beings. Most of the 

 cases in which this parasite 

 has been reported as occur- 

 ring in man may be traced 

 back to unrecognised Ascaris 

 lumbricoides, or to clots of 

 fibrin ; twelve certain cases, 

 however, remain. The case 



FIG. 2i i. Eggs of 

 Eustrongylus giga*s, 

 above seen from the 

 flat, below the opti- 

 cal section, 400/1. 

 (After Railliet.) 



recently described by Trumbull FIG. 2io.Eustron- 

 was probably not a case of g* ? & R 

 eustrongylus. 



We are not aware of . the source of infection, but we have 

 learned from Balbiani that the eggs develop an embryo in water 

 or moist soil, and that this embryo may remain alive several 

 years without hatching ; the infection of dogs with embryo-con- 

 taining eggs did not succeed ; an intermediate stage in fishes is 

 conjectured. 



