406 TRICOMA AND OTHER NEW NEMATODE GENERA, 



among the particles of the sand in which it lives. The great 

 lengtli of the cephalic hairs is a frequent characteristic of sand- 

 inhabiting species. I am uncertain about the nature of the lips, 

 but the mouth is capacious and in form like that of other species of 

 Monhystera. The distance of the circular lateral organs from the 

 anterior extremity is about equal to twice the width of the head ; 

 they have a central fleck and are one-third as wide as the forward 

 part of the neck. The cesophagus, which is two-thirds as wide as 

 the neck, presents a distinct chitinous lining and is separated 

 from the intestine by a shallow but distinct constriction. The 

 rather thick-walled intestine is two-thirds as wide as the body. 

 The ventral excretory pore is situated somewhat behind the 

 oblique nerve-ring ; the unicellular gland, for which it serves as 

 the outlet, lies behind the cardiac region. The lateral fields are 

 one-third as wide as the body. The anterior half of the tail is 

 conoid ; thence it is cylindrical and one-fourth as wide as at the 

 anus. The terminus is scarcely expanded and bears two hairs, 

 each one-half as long as the tail. Caudal glands are present. 

 Both the anus and the vulva are slightly depressed. The eggs 

 are one-half as wdde as the body, and somewhat longer than wide ; 

 they are deposited before segmentation begins. 



-^.g g.]^ 3.2 — 3:7 — 2^ 1-5 mm. The two equal linear spicula are of 

 nearly uniform size throughout, their proximse being scarcely 

 cephalated ; they are slightly bent near the middle and are one 

 and one-third times as long as the anal body-diameter. The 

 obscurely sigmoid accessory pieces are two- thirds as long as 

 the spicula, the plane in which they may be said to lie being 

 perpendicular to the body axis. In the distal half they are 

 parallel to the spicula ; thence they curve aw^ay from the spicula. 

 The blind end of the testicle lies as far behiud the cardia as the 

 latter is behind the nerve-ring. The anal region is elevated. 



jjah. — This worm is not uncommon about Port Jackson, New 

 South Wales, Australia, 1893, in marine mud and sand. 



^ -.r !• 7-4 19- -68-^^ 8 6- ^, ^,. 



5. M. GRACILLIMA, n.sp. 1-5 2-1 ¥b 3^ 2- I'^m^^- ihlS 



exceedingly graceful and fascinating species is characterised by 



