NO. 2131. 



NEMATODE PARASITES OF RODENTS— HALL. 



79 



species, in which case it would be difficult to say to which of these the 

 name O. flagellum should be applied. Schneider (1866), who rede- 

 scribed this species, does not comment on 

 this point, and I find no note on it in the 

 reviews of Nassonov's (1897) Russian 

 article. 



Nassonov has made a histological and 

 minute study of this species, some of his 

 findings being as follows : The mouth is not 

 papillate, as stated by Hemprich and Ehren- 

 berg, and its lumen is hexagonal instead of 

 triangular, as stated by Schneider (1866). 

 Histologically, the cuticle is found to consist 

 of two layers, which are quite independent 

 except in the lateral lines, where they unite. 

 In some places, especially near the genital 

 aperture, these layers are remote from one 

 another, the outer cuticular sheet bowing 

 out near the vulva, the space between such 

 separations being filled with a homogenous, 

 colorable substance. The matrix, or sub- 

 cutaneous sheet, consists of a layer of rela- 

 tively large cells, which are compressed to 

 the side, toAvard the middle and lateral fields, 

 in the muscular fields where the muscle 

 fibers attach directly to the cuticle. The 

 number of matrix cells in a cross section 

 varies according to the body region — in the 

 tail end there are 6, in the posterior region 

 of the body there are 

 8, and in the middle 

 and anterior region 

 there are 16. 



31 



OXYURIS HAMATA von 

 Linstow, 1879b. 



Specl'liG diagnosis. — 

 Oxyuris (p. 65) : Cuti- 

 cle transversely annu- 

 lated. Mouth with six 

 conical lips (fig. 92), 

 which turn outward to 

 form blunt h o o k - 

 shaped lamellae. The pharynx apparently communicates through 

 a constricted aperture with a dilated portion of the esophageal 



Fig. 91.— Oxtueis flagel- 

 lum. Female. Enlarg- 

 ed. After Nassonov, 

 1897. 



Fig. 92.— Oxyuris ham- 

 ATA. Anterior ex- 

 tremity OF female. 

 Enlarged. After 

 von Linstow, 1879. 



