FREE-LIVING FRESH-WATER NEMATODES 57 



most part single file. Nothing very definite is known concerning the form 

 and size of the eggs, but from the size of the apparently matured ova it is 

 assumed that the eggs are considerably elongated, perhaps two to two and 

 one-half times as long as the body is wide, and if so, it is unlikely that 

 more than one is contained in the uterus at a time. 



Habitat: Deer Bottom, Pikes Peak region, Colorado. Formalin to 

 glycerine. 



ONCHOLAIMUS, Dujardin, 1845. 



Fig. 14, Plate V. 

 13. Oncholaimus punctatus, n.sp. 



The rather thin., transparent, colorless layers of the naked cuticle appear 

 to be destitute of striations. It is rather difficult to observe the cuticle on 

 account of the presence in it of numerous dot-like elements, which near the 

 head are arranged in longitudinal groups, of which the widest is the lateral 

 group. The longitudinal arrangement of the granules, is continuous through- 

 out the body, but it is most marked on the lateral fields where there is a 

 definite band of them, having a width about two-fifths as great as the width 

 of the body. Each margin of this band is made up of a distinct longitudinal 

 row of granules arranged single file. The neck is slightly conoid, becoming 

 slightly convex-conoid toward the rounded head, which is not set off in any 

 way, or at most by an exceedingly obscure, broad constriction opposite the 

 pharynx. The six lips are distinct and well developed and have a distinct, 

 somewhat chitinous framework. They are arched together over the pharynx 

 in such a way as to produce a dome-like effect, the very thin and movable 

 flaps at the ends of the lips meeting together at the middle of the front of 

 the head. Opposite the middle of the amphids there is a transverse marking 

 or line which extends around the middle of the head. It is characterized by 

 staining somewhat more strongly with carmine than the other portions of 

 the cuticle. There are no eye-spots. The oesophagus begins at the base of 

 the pharynx with a diameter three-fourths as great as that of the base of the 

 head, and it continues to have this diameter until some distance behind the 

 nerve-ring. It then begins to expand gradually, so that finally it is about 

 three-fourths to four-fifths as wide as the base of the neck. The lining is a 

 distinct feature throughout the length of the oesophagus. There is a dis- 

 tinct conoid cardia, whose base is about half as wide as the corresponding 

 portion of the body. The intestine, which is separated from the oesophagus 

 by a deep and distinct constriction, appears to have rather thin walls and to 

 be composed of cells of such a size that probably six or more would be re- 

 quired to build a circumference. These cells contain numerous granules of 

 rather uniform size. 



The lateral fields are about two-fifths as wide as the body. The loca- 

 tion of the ventral gland has not been made out. The excretory pore is lo- 



