MESONCHIUM, PEPSONEMA 295 



cells containing numerous granules of rather uniform size, and of about the same 

 diameter as the dot-like lateral, cuticular elements. The conoid tail tapers from 

 in front of the anus and becomes cylindroid in the posterior third, where it is 

 one-seventh as wide as at the base. The elongated caudal glands, which empty 

 by separate ducts, are packed in the anterior half of the tail. Slender, rather 

 tapering setae, to the number of twelve occur on each ventrally submedian line 

 in front of the anus; about seven setae occur on each of the submedian lines on 

 the tail. The pre-anal setae are scattered through a distance about equal to the 

 length of the tail, and are mostly very inconspicuous, especially anteriorly. The 

 lateral fields are two-sevenths as wide as the body. The non-granular, ellipsoidal 

 renette cell occurs near the cardia, and is one-third as wide as the base of the neck. 

 The large, rather conspicuous, elevated vulva leads into a large, conoid, muscu- 

 lar, more or less cutinized vagina, which extends inward half way across the body. 

 It is probable that the prolate eggs are about as long as the body is wide, but there 

 is some uncertainty about this. An unusual feature is that the ovaries are 

 reflexed only near their blind ends. Each contains about twenty ova, arranged 

 more or less single file. The tail of the male is cylindroid in the posterior two- 

 fifths, where, at its widest, it is only one-tenth as wide as at the anus. The rather 

 long, slender, uniform, more or less acute, colorless spicula are straight to near 

 the middle, but are arcuate distally. Their proximal ends appear to lie more or 

 less ventrad from the body-axis. The rather strong, slender accessory piece has 

 an applied part one-fourth to one-third as long as the spicula; its uniform, more 

 or less blunt, rather slender apophysis bends and extends backward parallel to 

 the body-axis. The proximal extremity of the apophysis lies dorsad from the 

 body-axis. To be seen along the posterior half of the region occupied by the 

 oblique copulatory muscles, is a pre-anal series of almost invisible ventral inner- 

 vations, the distances between which are about equal to one-third the body-diam- 

 eter. The space occupied by the oblique copulatory muscles is about two and 

 one-half times as long as the tail. 



Habitat: Marine algae, Key West, Fla., U. S. A. Flemming to glycerine jelly. 

 Fig. 76, p. 294. 



77. Pepsonema pellucidum n. sp. Cuticle of medium thickness. Anteriorly 

 the number of the longitudinal rows of "beads" appears fewer than near the tail, 

 where there are sometimes six 

 or possibly eight rows. Forma- 

 tion of the cuticula like that 

 found in the genus Spilophora. 

 Somatic setae very minute. , , 

 Lips six, or three and two- 

 parted. Mouth-opening about 

 one-fourth as wide as the front 

 of the head, and leading into a 

 minute vestibule, which is X 750 

 nearly twice as wide as the mouth opening and very shallow. The pointed, 

 cutinized apices of three inner lips come together in this vestibule; they are of 

 nearly equal size, the dorsal being only slightly larger than the two submedian 

 ones. It may possibly be questionable whether this genus should not be placed 

 in the Anaxonchia. At the base of the pharynx, there are one or two minute, 

 onchium-like processes, which are so small as to be easily overlooked. The 

 oesophagus continues to have the same width, or to decrease slightly, until it 



