AET. 16 HELMIISTTH PARASITES OP THE OPOSSUM — CHANDLER 



11 



in length, and long enough to reach to the basal portions of the 



second row of scales following. The scales continue to be of this 



form, although becoming gradually shorter (fig. 5, C) until very 



near the region where they begin to dwindle and disappear. Here 



the points are rather suddenly reduced to three, then to two, and 



finally there are a few rows of diminutive simple spines, which soon 



disappear (fig. 5, D and E). In 



the esophageal region the rows of 



scales are spaced about 40/i, to 43/a 



apart, but behind the esophagus 



the rows are closer together, about 



28ja to SOjU, apart, and the scales 



are closer together in the rows, so 



that this portion of the body has 



a more densely scaled appearance. 



Cervical sacs 1.35 mm to 1.55 



mm in length, measured from the 



posterior border of the head bulb. 



Esophagus club-shaped, 4.2 mm 



to 4.6 mm long, with a maximum 



diameter, near the distal end, of 



about 800/A. 



Male, 25 to 31.5 mm long, and 

 1 to 1.1 mm in maximum diam- 

 eter, which is near the posterior 

 end of the esophagus. Bursa 

 covered with minute spines along 

 the cuticular striae on the ventral 

 side, except just behind the clo- 

 acal opening. There are four 

 large, coarse, caudal papillae on 

 each side, the most posterior one 

 being slightly smaller than the 

 others and spaced a little apart. 

 There is a pair of small ventral 

 papillae near the base of the most 

 posterior lateral papillae, but a 

 second pair of these, as described for G. spinigerum, could not be 

 seen. Cloaca about 400ju, from posterior end. The short right 

 spicule, 700/x to 800/x in length, tapers gradually for its entire length 

 and has no abrupt narrowing. It is about 50/* broad at the base 

 and ends in a bluntly rounded tip. The long left spicule is 2.2 to 

 2.5 mm in length, and it also tapers gradually for its entire length; 

 it is llOfx broad at the base and ends in a bluntly rounded, almost 

 truncated tip. 



V 



V 



)0y" 



FiGUUE 5. — Spines from various parts of 

 body of Q-nathostoma didelphis, with 

 spines from corresponding parts of body 

 of Qnathostoiiia spinUjcrum shown at 

 right : A, From shortly behind head 

 bulb ; B, from a few rows farther pos- 

 teriad ; C. from near middle of spiny 

 portion of body ; I>, from near posterior 

 part of spiny region of body ; E, from 

 terminal rows of spines 



