494 



PROF. C. L. BOULJi:NGEE ON FILAlillD 



of the last pair are small and flat ; they no doubt correspond to 

 the similar pair at the posterior extreniit}^ of the female. The 

 eight anterior pairs of papilke are elongated and decrease in size 

 from before backwards. 



The two spicules are very unequal, measuring 0'38-0'42 mm. 

 and 0-13--0'14: mm. respectively. The long spicule consists of an 

 anterior tubular region followed by a pai-tly membranous posterior 

 region. The small spicule is conical and terminates in a point. 



Female 160-175 mm. in length, with a maximum thickness of 

 about 0'7 mm. The (esophagus measures 1'5-1*7 mm. in length. 



Anus about 0T5 mm. from the posterior extremity, the latter 

 rounded and provided with a pair of small flat papillae. At the 

 level of the anus the body has a thickness of 0'2 mm. 



Yulva l-9-2*4 mm. from the anterior extremity. The slender 

 vagina has a forwardly directed loop which extends to the level 

 of the nerve-ring, 0*4 mm. from the oral end. 



Ovoviviparous. Eggs thin-shelled, measuring 0'022 mm. x 

 0-015 mm. 



Genus AcANTHOCHEiLONEMA Cobbold, 1870. 



ACANTHOCHEILONEMA DIACANTHA (Molin, 1858). 



Film'ia diacaiilha was originally described from worms obtained 

 in the abdominal cavity and lungs of various Rodents in Brazil. 

 The specimens from the Society's Gardens are from the Canadian 

 Porcupine, Erethizon dorscUum^ and \vere found in the peritoneal 

 cavities. 



The original description is somewhat incomplete, and Hall, in 

 his monograph of the Nematode parasites of Rodents (1916), is 

 inclined to regard this form as a species of Setaria ; the well pre- 

 served material before me makes it, however, quite clear that the 

 worm is to be referred to Cobbold's genus Acanthocheilonema as 

 recently redefined by Railliet, Henry, and Langeron (1912). 



^'pecijic diagnosis. — Acanthocheilonema : Body slender, filiform, 

 diminishing in breadth at both extremities and much attenuated 

 posteriori}'. Anterior extremit}^ somewhat claviform, the head 

 being separated from the rest of the body by a slight, neck-like 

 constriction. 



The cuticle appears longitudinally lined under a low power of 

 the microscope ; nigh magnifications, however, reveal a very fine 

 transverse striation. 



H'yx head-papilhe are present, four submedian and tw^o lateral. 

 The lateral papilke are large and project in such a way that the 

 head appears almost square in dorsal or ventral view. 



The (jesophagus consists of distinct anterior and posterior 

 regions ; the former is narrow and measures under 0*5 mm., the 

 posterior region is stouter and has a length of 2-3 mm. The 

 nerve-ring surrounds the middle of the anterior part of the oeso- 

 phagus. 



