1922.] 



H. A. Baylts and R. Daubney: Parasitic Nematodes. 



333 



0-1 mm. 



minutus 



Fig. 67 . — Diaphanocephalus 

 Head of female ; dorsal view. 



b., wall of buccal capsule; d 

 dorsal oesophageal gland; p., papilla; s., 

 wall of buccal capsule in optical section. 



duct of 



dorso- ventral position it is roughly oblong. The 



central portion of the cavity extends some little 



way into the oesophagus. The duct of the dorsal 



oesophageal gland projects for more than half 



the length of the buccal capsule. It is supported 



by the wall of the capsule, which is considerably 



thickened (figs. 67, 68) dorsally and ventrally 



at its base s. Viewed laterally, the buccal 



capsule appears roughly triangular, with the 



apex of the triangle directed backwards. The 



oesophagus is short and club-shaped, measuring 



about o*45 mm. in length, whilst its maximum 



thickness is about 0*15 mm. The nerve-ring sur- 

 rounds the oesophagus at about 0*09 mm. from 



its anterior end. The excretory pore opens at 



about 038 mm. from the head end in the male, 



and 044 mm. in the female. The bursa of the 



male is completely campanulate and not easily 



spread out. There are three lobes, two lateral 



and an unpaired dorsal. Themain trunk of the dorsal ray (fig. 69) is extremely large, 



measuring about 02 mm. in length, and up to 007 mm. in thickness just before it gives off 



the large externo-dorsal rays. The lat- 

 ter are given off high up (about o - i6 mm. 

 from the tip), and at a wide angle. 

 Almost immediately behind this point the 

 main trunk gives off a pair of stout, 

 curved branches which together form a 

 large horseshoe ; the tips almost reaching 

 the margin of the bursa. At its tip the 

 dorsal ray divides into two short curved 

 branches, the tips of which are again 

 bifurcated. The lateral rays originate 

 from a common root and reach almost to 

 the edge of the bursa. The ventral rays 

 are long and slender and closely applied 

 to each other throughout their length 

 They reach the margin of the bursa. 

 Just anterior to the origin of the bursa, 

 there is a pair of latero- ventral papillae, 

 which are stalked, and, though small, 

 quite prominent. 



The spicules are equal and slender and 

 measure 0255 to 0*275 mm. in length. 



j 



o-lrnrrv. 



Fig. fi8. — Diaphanocephalus minutus. 

 female; lateral view. 



Lettering as in fig. 67. 



Head of 



