MARGONEMA, LEPTOGASTRELLA 



249 



is uniform and one-fourth as long as the corresponding body-diameter. There 

 are thirty to forty low, about equidistant supplementary organs, of such a char- 

 acter that the ventral contour becomes crenate when the tail end is incurved; 

 the crenations are then nearly contiguous. There are a few, scattered ventrally 

 submedian setae on the tail. The acute ends of the spicula are minutely and 

 sharply curved through an angle of 180 degrees at the very tip. One male speci- 

 men was seen in which there were two renette cells, each with a separate duct for 

 some distance. 

 Habitat: Salavery, Peru. Marine. Sublimate to balsam. Fig. 27, p. 248. 



28. Leptogastrella pellucida n. sp. Except for the setae near the head and on 

 the tail of the male, the cuticle appears to be naked. The neck is cylindroid 

 posteriorly, becoming faintly convex-conoid toward the rounded head, which 

 may be set off by an almost imperceptible, broad constriction opposite the base 

 of the pharynx. The membranous lips, are either six in number, or three and 

 each two-parted. The oesophagus is cylindroid. There is an elongated cardia, 

 one-half as long as the body is wide, and about two-thirds as wide as long. The 

 intestine, separated from the oesophagus by a shallow constriction, becomes 

 at once two-fifths as wide as the body, and then diminishes slightly so that it has 

 about one-third the width of the body. Its cross-section would appear to be 

 made up of not more than two cells. The intestine is so narrow as to give the 

 nema quite an unusual appearance. It is thick-walled and has an exceedingly 

 narrow lumen. Its cells are packed with exceedingly minute yellowish granules. 

 Correspondingly, the body-wall is unusually thick and muscular, and slightly 

 oblique longitudinal striations due to the refractions of the muscular fibres can 



3-3 



..9-?.? 1.2.. 



1.3 9. .... .-. . 



'2. 2.5 2.9 3-* " 2- 



be seen throughout the length of 

 the body. The lateral fields 

 appear to be about one-third as 

 wide as the body. The renette 

 has not been seen. Vulva slightly ^ 

 elevated. The outstretched ovary 

 contains forty or more ova 

 arranged single file. The blind / cdl 

 end of the ovary lies not far behind 

 the nerve-ring. The eggs occur- 

 ring in the uterus appear to be <K ............. 



about as long as the body is wide 

 and one-third to one-fourth as 

 wide as long. The tail of the 

 male is conoid to near the termi- 

 nus, where it has a diameter about 

 one-fifth as great as at the anus. 

 Caudal glands are located in the base of the tail. There are no supplementary 

 organs, nor have any special papillae or setae been seen either in front of the 

 anus or behind it. The spicula slide in tubular accessory pieces. 

 Habitat: Marine mud, San Pedro, California, U. S. A. At first glance this 



