BY VERA IRWIN SMITH. 



555 



at the cephalic end is still visible in most of the preserved specimens, and does 

 not appear to have shrunk at all in the glycerine jelly mounts from which the 

 measurements and drawing (Text-tig. 1) were made. Males measured from 

 6.2 to 6.8 mm. long, with a maximum wituh, in front of the caudal bursa, of 

 0.072 to 0.083 mm. ; females, 12.3 to 16.2 mm. long, with a maximum width of 

 0.143 mm. in the region of the genital pore. Cephalic swelling, 0.093 to 0.104 

 mm. long and 0.046 to 0.052 mm. broad; oesophagus, 0.352 to 0.400 mm. in the 

 male, 0.430 to 0.510 mm. in the female, with an average width of 0.020 mm. ; 

 nerve ring, 0.230 to 0.260 mm., and excretory pore, 0.268 mm. from anterior end. 

 The diameter of the body just behind the cephalic enlargement is 0.040 mm. in 

 males, 0.049 mm. in females. The female genital aperture is situated 2.25 to 

 3.33 mm. and anal aperture 0.140 to 0.156 mm. from tip of tail. The cuticle 

 is marked by a fine transverse striation at intervals of 0.0015 mm., except on the 

 anterior swelling, where the striae are much coarser. Stevenson describes only 

 longitudinal markings, which are also visible on these specimens. The terminal 

 portions of the two divergent uteri, which form the ovijectors, differ slightly from 

 the figures given by Stevenson. Each consists of three parts (Text-fig. 2); the 

 first, opening at the vulva with very thick muscular walls, is about 0.220 mm. 

 long, and is separated by a sphincter, in the form of a prominent, ring, from a 



Text-figs. 4-6. — Cephalostrongylus quadriradiatus. 

 Posterior end of male, side view, (x 200) ; 5. The same, dorsal view. (x200). 

 j'.Z'., ventre- ventral ray ; I. v., latero-ventral ray; f./. , externo-Iateral ray; 

 ni.L, medio-lateral ray; p. I., postero-lateral ray; e.d., externo-dorsal ray ; 

 d.r,, dorsal ray; 6, male spicules and chitinous support, (x 380). 



narrower, but still muscular part 0.117 mm. long, which is continuous with the 

 uterus. Eggs contained in this part of the uterus measure 0.067 by 0.039 mm., 

 and are still in the early stages of segmentation . The genital pore is a transverse 



