272 



ORDER POLYLAIMIA 



small size and their overlapping. Amphids forward-pointing, minute, difficult 

 to see. The oesophagus becomes slightly narrower where it passes through the 

 nerve-ring; posterior bulb napiform, three-fourths as wide as the base of the 

 neck. There is no distinct cardia. The thick-walled intestine becomes at once 

 about two-thirds as wide as the body, and its cross-section is made up of about 



Wj? 



four cells, which are 

 packed with granules 

 of uniform size. The 

 lateral fields are about 

 one-third as wide as the 

 body, and contain a 

 series of cells of large 

 size. The nerve-ring 

 surrounds the oesoph- 

 agus obliquely. There 

 is a single, small, elon- 

 spn gated, very inconspic- 

 uous ventral supple- 

 mentary organ of the 

 ordinary kind opposite 

 the posterior part of 

 the spicula, and in 

 ; front of it a number of 

 minute ventral setae. 

 Seven pairs of sub- 

 ventral tubular sup- 

 y 7 cft plements occur on the 

 tail. The ejaculatory 

 duct is about two-fifths as wide as the body. The caudal glands are evidently 

 located in front of the tail, but their exact position has not been made out. 



Habitat: Marine sand about the bases of algae, in surf, Island off Port Royal, 

 Jamaica. This genus resembles Laxonema in many respects, and also resembles 

 Laxus but differs in the form of the lateral organs and in other ways. Sublimate 

 to balsam. Fig. 56. 



57. Zalonema nudum n. sp. Cuticle naked. The face view of the striae gives 

 the impression of a series of narrow, contiguous hoops. The cuticle becomes 

 thicker on the neck, and much thicker on the head. Lips, thick, small, plain. 

 On the male there are very distinct and prominent wings, beginning about three 

 times as far in front of the anus as the terminus is behind it. Each wing extends 

 backward and ends opposite the proximal ends of the spicula. The width of 

 this wing is about equal to the corresponding thickness of the dorsal or ventral 

 cuticle as seen in optical section. None of the irregularities in the wall of the 

 pharynx are suggestive of the ordinary pharyngeal organs, and yet they are very 

 distinct features. Two of them are rather prominent, one on the dorsal side, 

 opposite the anterior portion of the cephalic thickening, and the other on the 

 ventral side opposite the middle or posterior portion of the cephalic thickening. 

 The oesophagus continues with the same diameter until it expands to form the 

 very broadly pyriform or napiform cardiac bulb, which is three-fourths as wide 

 as the base of the neck. The lining of the oesophagus occupies nearly one-third 

 of the optical section. The oesophageal lumen continues through the bulb. 



