IONEMA 235 



.2 5-9 7.W "'y?'' 92. 



9. lonema ocellatum n. 8 p. "*""'"" i-"" i's L' > a " The thin cuticle is 



naked except for the cephalic setae. There are no traces of lips. The amphids 

 are very inconspicuous. The neck is cylindroid posteriorly, and convex-conoid 

 anteriorly, especially near the head. The eye-spots are light brown in color, 

 and each has a refractive element in front. In the pigmented portion of each 

 eye there is a more or less central nucleus with a subsidiary, small companion 

 object. The cylindroid oesophagus is at first one-third, near the nerve-ring one- 

 fourth, and finally one-fifth, as wide as the corresponding portion of the body. 

 Its lining is indistinct. There is no cardia. Owing to the presence of large 

 somatic glands, observation of the junction of the oesophagus with the intestine 

 is difficult. The collum appears to be one-fifth as wide as the corresponding 

 portion of the body. The intestine is two-thirds to three-fourths as wide as 

 the corresponding portion of the body, and is thick-walled, and has a very faint 

 lumen. The cells of the intestine, which appear somewhat as if overlapping, 

 contain more or less uniform, yellowish, scattered granules; they have large, 

 spherical, granular nuclei with conspicuous nucleoli. The arcuate, conoid tail 

 tapers from the anus to the unarmed convex-conoid terminus. The conoid spin- 

 neret is simple in structure. The ellipsoidal caudal glands occur in a loose tan- 

 dem series in the anterior half of the tail. There are no caudal setae. The lat- 

 eral fields are two-fifths as wide as the body. The granular, elongated, pyriform 

 renette is one and one-half times as long as the body is wide, and one-half as wide 

 as long. It is not reflexed and lies near the middle of the body, a little in front 

 of the flexure of the front ovary. The nerve-ring is of medium size and is accom- 

 panied by rather obscure nerve cells. From the small, elevated, more or less 

 inconspicuous vulva the medium-sized vagina leads inward half m ^ 

 way across the body; it is more or less strongly cutinized. The ; 

 size, form and covering of the eggs is unknown, but the ripe ova set (4)' 

 are about as long as the body is wide. The broad, cylindroid 

 ovaries extend five-sixths the way back to the vulva, and con- " moe 

 tain about twenty ova, arranged single file in the proximal half, ^ 

 but irregularly in the distal half. The duct of the renette is 

 necessarily very long and is slender; there is a distinct, elon- oe 

 gated ampulla, with a very long and very slender duct leading 

 from it to the pore. This latter duct is about as long as the 

 body is wide. This genus, of which there are several species, spn 

 is made very remarkable by the possession of a pair of relatively 

 huge glands filling most of the body cavity behind the base of X75 

 the neck and ending two and one-half times as far behind the neck as this latter 

 is behind the head. The points of exit of these glands appear to be at the head 

 end. Each gland has a nucleus near its blind end. In the vicinity of the nerve- 

 ring the glands diminish in size, and half way from this point to the head appear 

 to come to a narrow, rounded end, strictly lateral in position, and from thence 

 there appear to be narrow ducts leading toward the lip-region to pores, where 

 foreign particles are seen to cling, and which are designated in the drawing 

 as amphids. Near the middle these glands are pressed to one side by two sub- 

 dorsal cells, apparently nerve cells. 



Habitat: Marine algae, Panama. Hot sublimate to balsam. This genus is of 

 wide occurrence in tropical oceans; specimens from both the East and West 

 Indies are known to the writer. While specifically different, these forms do 

 not vary much one from another. Fig. 9. 



