

16 ANTARCTIC MARINE 



AUSTRONEMA, new genus 



The single species for which this new genus is proposed has many of the char- 

 acters of Monhystera, but differs in so many important respects as to call for 

 separate classification. The principal differences of generic value are the pos- 

 session by Austronema of an oesophagus altered in the posterior half, a well 

 developed ventral gland, special lateral cells, hamate spicula without acces- 

 sory pieces, and glandular (?) organs associated with the spicula. Other minor 

 differences exist, such as the occurrence of the special group of setae near the 

 middle of the tail. The following is the type species. 



6. Austronema spirurum, n. g., n. sp. The cuticle is traversed by exceedingly 

 minute transverse striae. The lips are confluent. The conoid neck contains a 



cylindroid oesophagi!?, whose di- 

 ameter measured near the nerve- 

 J 4 ring is one-half as great as that of 



87 3 the corresponding portion of the 



2'; 2"* ' 8nn ' neck, but which finally becomes 



two-thirds as wide as the base of 

 the neck. There is a break in the musculature of the oesophagus just behind 

 the nerve-ring, and behind this break the refractive nature of the lining is some- 

 what different, and, moreover, in many of the preserved specimens the diameter 

 of the oesophagus from this point onward is suddenly somewhat greater. There 

 is a conoid to cylindroid cardia about one-half as wide as the base of the neck. 

 The very thick-walled intestine, two to four cells in girth, becomes at once three- 

 fourths as wide as the body. For a short distance behind the cardiac collum, 

 namely, for a distance about equal to two-thirds the body width, the tissues of 

 the intestine do not stain. The lining of the intestine is refractive and distinct, 

 so that the almost imperceptibly zigzagged lumen can be readilv followed. The 

 intestine is separated from the oesophagus by a collum two-fifths as wide as tKe 

 base of the neck. The size of the numerous, yellowish, uniform granules contained 

 in the intestinal cells varies in the different parts of the intestine; they are much 

 coarser posteriorly than anteriorly. From the anus, the posterior lip of which 

 is elevated, the chitinized rectum extends inward and forward a distance equal 

 to the anal body diameter. 



The tail tapers in such a manner that at the middle its diameter is about half 

 as great as at the base. Its terminus is about one-fifth as wide as its base. The 

 ellipsoidal caudal glands are arranged in a loose tandem in the anterior third of 

 the tail. Very short, stiff, inconspicuous, ventrally submedian caudal setae 

 occur on each side of the tail, two on the anterior half of the tail, and three near 

 the middle and close together and finally, one or two on the cylindroid, narrow, 

 posterior half. The pyriform to ellipsoidal granular renette-cell is located at a 

 distance behind the base of the neck equal to one and one-half body-diameters. 

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

 long, and presses the intestine considerably to one side. It does not appear to 

 have any companion cell. The medium sized nerve-ring surrounds the oesopha- 

 gus somewhat squarely, and is accompanied by distinct nerve-cells extending 

 well back toward the base of the neck. From the rather small, but rather con- 



