60 ENTOZOA OF EATS AND MICE. 



such a small animal as a mouse, carries fifteen or sixteen 

 of these relatively large worms (uieasuring between an inch 

 and an inch and a-half) in its stf)mach. its movements are 

 likely to 1)e impeded. I have fre([uently seen the stomach 

 in a balloon-like condition OA\ing to extreme distension, 

 the nenuitodes l)eing easily visil)le through the thin walls. 



Heferal'is spvmo.m Schn. 



Though Hall (IIHO. ]). 47) does not quote this nematode 

 as a parasite of the mouse 1 have found it on a few occasions 

 in this host in Sydney (J. Um)a, p. 417 : 19106, p. 8(>). 

 From August 11)09 to Feb. 1910 I found this roxuidworm once 

 in 119 Ep. raff us examined: once in lOO Ep. alexandrinus ; 

 once in the mouse. 73 being examined ; and thirty times in 

 Ep. norvegict(s (121 examined). It is thus essentialh' a 

 parasite of the Ijrown rat Avhere it occurs commonly 

 (25%), sometimes in abinidance, the greatest number 

 actualh" counted from one host being 266 (Oct. 1909). 

 There are usually from two to eight present. 



Lane (1914. p. 660) described a roundworm Gangv- 

 leterakis gangula from Mt(s denimanus in India Init it is 

 undoul)tedly //. spumosa as Hall has already pointed out. 



Oxyuil.H {Syphacia) fefrapfera, Nitzsch. 



This small roundworm has not previously been recorded 

 from Australia. I have taken it on many occasions from the 

 mouse in Sydney district where it appears to he much less 

 common than O. obvelatu. 



Oxyuris (Syphacia) ohvelafa Br. 



The following results were obtained in vS\'dney during 

 August 1909-Februarv 1910. 0. ohvelafa was found in 

 11 out of 119 Ejj. raff'us : tA\o out of 100 Ep. alexandrinus : 

 two out of 121 Ep. norvegicvs and nineteen out of 73 Jlns 

 musculus. 



The percentage infections are thus approximateU- 10, 

 2, 1.6 and 26. These Oxyurids appear to be essentially 

 parasites of the mouse and house rat. The greatest numbers 

 counted from one host during the period were 340 (from an 

 Ep. rattus), 276 [E. rattus), 76 {E. rattus), 62, .51 and 41 

 (from mice). There are usually found from one to six. 



