ANTOMICRON 241 



17. Antomicron pellucidum n. sp. ** 2 -* 2 ~? 2-? ^O 1-1 " Except for the 

 cephalic setae the cuticle is naked. On the ventral side of the distinctly pro- 

 jecting wing there is a subordinate line to be seen throughout the greater por- 

 tion of the length of the body, which is not as conspicuous as the main part of 

 the wing. Neck conoid. The very minute pharynx (?) is apparently conoid; 

 whether armed or not is unknown. The lip-region has not been examined with 

 success on account of deficient material. That portion of the amphid inside the 

 two ellipses stains more strongly than the tissues elsewhere. The borders of the 

 two amphids approach each other so closely on the dorsal side that they some- 

 times almost touch, in fact appear to be connected by a special ^s^g^ 

 cuticular element. Oesophagus cylindroid for some distance back, (^^^'^ '' 

 and then expanding rather suddenly to form an almost impercep- 

 tible swelling near the beginning of the middle third of the neck; 

 thereafter it diminishes almost imperceptibly to near the nerve- 

 ring, then begins to expand gradually until near the end, where it 

 rapidly expands to form an obscure, small, elongated, pyriform 

 cardiac bulb, almost half as wide as the base of the neck. There 

 is a rounded cardia one-fourth as wide as the base of the neck. 

 Considering the size of the oesophagus its lining is prominent. 

 The intestine is separated from the oesophagus by a broad, shallow constriction, 

 and soon becomes half as wide as the body, and apparently would present only 

 two or three cells in cross-section. The lateral fields appear to be nearly one- 

 third as wide as the body. It seems probable that a renette cell occurs at some 

 distance behind the base of the neck, but no excretory pore has been seen. The 

 tail of the male is conoid to near the terminus. The caudal glands are located 

 in an open tandem series in front of and behind the anus. The eight supple- 

 mentary organs occupy a distance nearly four times as great as the length of the 

 tail; each is a nearly straight, cutinous tube, half as long as the body is wide, 

 arranged at an angle of forty-five degrees with the body axis, and having its 

 distal extremity protruding backward slightly through the cuticle. The organs 

 taper slightly in the vicinity of the distal end, which is suddenly somewhat 

 ventrally arcuate at the terminus. They are probably protrusile, though they 

 have not been seen in a protruded position. These tubes have a diameter approx- 

 imately equal to the width of one of the adjacent annules of the cuticle, and their 

 proximal ends show indications of an attachment extending forward. There are 

 a number of specially-developed setae in the vicinity of the anus; especially 

 prominent are two submedian setae, one on each side of the anus, one-third as 

 long as the anal body-diameter. A little in front of these is another pair, one on 

 each side, of slightly smaller size, and on the tail there are a few similar ven- 

 trally submedian setae of smaller size. Spicula a little longer than the anal body- 

 diameter, and tapering to a point in their distal thirds. The accessory piece 

 surrounds the spicula in their distal fourths, and then extends forward to the 

 dorsal side of the body from the middle of the spicula at a small angle. The 

 appearance of the proximal portion of the accessory piece somewhat resembles 

 that of the proximal ends of the spicula, though it is straighter and more solid. 

 From its cephalated proximal end a muscular strand joins the body wall on the 

 dorsal side of the anterior portion of the tail. The posterior testis is the 

 smaller. 



Habitat: Marine; Punta Arenas, Pacific Coast of Costa Rica. Unfortunately 

 the single specimen examined is of such a character that the details of the 

 pharynx must be left undetermined. Fig. 17. 



