22 



Cobb —Nematodes, mostly Australian and Fijian. 



9. D. fluviatilis, de Man. 



1-8 mm. Cuticle vGrj finely transversely 



1.1 1. 2-1 ? 



striated ; neck conoid, diminishing much ; cephalic setae two, lateral ; lateral organs 

 small clefts, alike in both sexes ; pharynx with two large teeth of equal size, both 

 edged and pointed and crossed when at rest, in the living state continually biting 

 together; wall of the pharynx in front of the teeth longitudinally striated; portion 

 of the oesophageal tube behind the stout median bulb two-thirds as long as the 



remainder; tail conical to the hair-fine terminus; oviparous. 



With 



the exception of two small pairs near the middle of the tail, all the male papillae are 

 bristle-shaped. The bristle-shaped papillae are arranged as follows : one pair sub- 

 median just in front of the anus, one pair lateral just in front of the anus ; one pair 

 submedian a little behind the anus, one pair submedian near the middle of the tail, 

 one lateral pair between the two pairs last mentioned, and, finally, one lateral pair 

 far back. Spicula stout, plump, arcuate ; accessory pieces long, rod-shaped. 



Hab. — Found in water, Holland ; less common than D. rivalis. 



10. D. trichuris, n.sp. 



8-7 12- ■28-'^^ 

 2-8 2-8 3-1 



1-6 mm. The cuticle is traversed longi- 

 tudinally by about forty wings and transversely by numerous striae. The convex- 

 conoid head bears four very short and inconspicuous spreading submedian cephalic 

 setae arranged opposite the apex of the conspi- 

 cuous dorsal tooth. Six labial papillae surround 

 the mouth-opening, which is longitudinally 

 striated inside and supported by longitudinal 

 ribs. The elongated-elliptical lateral organs, 

 one-eighth as wide as the head, are situated 

 parallel to and opposite the middle of the 

 pharynx. This latter is narrow, being only 

 one-fourth as wide as deep, and contains a single 

 large hamate dorsal tooth whose apex is nearly 

 on a level with the lips. This tooth is so large 

 as to pretty well close up the mouth opening. 

 All the organs in the neck are quite typical. 

 The ellipsoidal median and cardiac bulbs are of 

 nearly equal size : though the cardiac if any- 

 thing is the larger, the median is manifestly 

 the more perfectly developed ; they are two- 

 thirds to three-fourths as wide as the neck. 

 The portion of the oesophagus between the 

 pharynx and the median bulb is one-half as wide as the neck and about twice as 

 wide as that part between the two bulbs. The intestine is two-thirds as wide as 



a, labial papiUa. 

 6, cephalic seta. 



c, one of the ribs of the pharynx. 



d, lateral organ. 



e, median bulb. 



f, nerve-ring. 



g, excretory pore. 

 h, cardiac bulb. 

 i, i, dorsal tooth, 

 y, salivary gland (?). 

 h, pharynx. 



I, organ of unknown function. 

 m, reflexed blind end of testicle. 

 n, proximal end of spioulum. 

 0, 0, anterior group of male 



papillje. 



•p, preanal ventral papilla. 



5, J, q, median group of male 

 papillae. 



r, supposed outlet of gland. 



s, posterior group of male pa- 

 pillae. 



t, hind end of testicle. 



M, ejaoulatory duct. 



V, anus. 



w, anus, female. 



X, gland (?). 



y, outlet of same. 



z, terminus. 



Fig. 3. — I, male DipZo^asier trichuris; II and 

 III, head and anal region of the same, more highly 

 magnified ; IV, anal region of the female of the 

 same worm. 



