62 NORTH AMERICAN 



are slightly more nearly approximated to each other posteriorly. These 

 organs are not conspicuous features, and scarcely disturb the ventral con- 

 tour. It is possible that each is connected with a unicellular glandular struc- 

 ture nearby. The two equal, tapering, somewhat arcuate spicula are one and 

 one-third times as long as the anal body diameter. Their proximal ends 

 are cephalated by expansion. The accessory pieces alongside are four-fifths 

 as long as the spicula, and somewhat broader than the spicula. In their 

 widest part they are one-sixth as wide as the corresponding portion of the 

 body. They are of rather uniform width throughout. There is a slight 

 constriction near each end, and the distal extremity appears to be very 

 minutely dentate. The spicula are about half as wide as the accessory pieces. 

 The ejaculatory duct is two-thirds as wide as the corresponding portion of 

 the body, as is also the testis. The blind end is as far behind the base of 

 the neck as this latter is behind the anterior extremity. 



Habitat: Silver Springs, Fla. Flemming solution to glycerine. 



ETHMOLAIMUS, de Man, 1880. 



Fig. 19, Plate VII. 



27 



16. Ethmolaimus americanus, n.sp. '- - : .6 mm. 



2.4 3.4 3.9 5.6 2.1 



The thin, transparent layers of the practically naked cuticle are tra- 

 versed by very fine transverse striae, resolvable with high powers into rows 

 of closely set dots, which are not modified on the lateral fields. Near the 

 head the dots are a little coarser than elsewhere on the anterior portion of 

 the body. On the tail the dots are much farther apart and, though really 

 arranged in transverse rows, at first glance appear to be scattered irreg- 

 ularly. The conoid neck ends in a somewhat truncated head, which bears 

 on its outer margin a circlet of four slender, spreading submedian cephalic 

 setae, each about half as long as the head is wide. There appear to be 

 twelve minute papillae in the lip region, which when folded together forms 

 a rather small, cyathiform cavity, in the midst of which stands the thumb- 

 shaped, forward-pointing dorsal tooth. This tooth is attached to a dis- 

 tinctly thickened rib of chitin, which extends from the lip region back to the 

 base of the pharynx, and is thicker anteriorly than it is posteriorly. This 

 thickened dorsal rib causes the pharynx to appear somewhat more strongly 

 built on the dorsal side than on the ventral side. The tooth tapers slightly 

 to a blunt point, and has a length about one-fourth as great as the width of 

 the front of the head. Behind it the pharynx is somewhat prismoid and 

 approximately one-fifth as wide as the head. It ends abruptly at the base. 

 The pharynx is surrounded by a pharyngeal bulb, the musculature of which 

 is set off distinctly from that of the oesophagus, in addition to which there is 

 a constriction between the bulb and the oesophagus. The somewhat obscure, 

 slender, apparently spiral amphids consist of about one and one-half winds. 

 They are located opposite the posterior portion of the pharynx, and are one- 



