494 PROF. C. L. liOULENGEK ON FILAIUID 



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

 the similar pair at the posterior extremity of the female. The 

 eight anterior pairs of papilla? 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 partly 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 oesophagus measures 1*5-1 "7 mm. in length. 



Anus about 0*15 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. 



Vulva 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 Oobbold, 1870. 



ACANTHOCHEILONEMA DIACANTHA (Molin, 1858). 



Filaria cliacantha was originally described from woi'ms obtained 

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

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

 Porcupine, Erethizon dorsatiivi, and were 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 Setarla ; the well pre- 

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

 w^orm is to be referred to Oobbold's genus AcantJtocheilonema as 

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



S'pecific diagnosis. — Acanthocheilonema : Body slender, filiform, 

 diminishing in breadth at both extremities and much attenuated 

 posteriorly. Anterior extremity 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. 



Six head-papillee are present, four submedian and two lateral. 

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

 head appears almost square in dorsal or ventral view. 



The oesophagus consists of distinct anterior and posteiior 

 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. 



