300 



ORDER APONCHIA, ORDER TRIPLONCH1A 



resembling the first member of the series, and behind this one or two others 

 arranged tandem. This entire series occupies a distance equal to the length of 

 the neck. From the raised vulva the vagina extends inward and forward. The 

 outstretched ovary contains fifty or more developing ova arranged in double 

 file, except near the blind end, which is located near the middle of the body. 

 The eggs are of large size, elongated, about one and one-half times as long as the 

 body is wide and about two-fifths as wide as long. In all those thus far seen the 

 spherical nucleus is of unusually large size. There is no posterior rudimentary 

 branch to the sexual organs. Well-developed accessory pieces surround the dis- 

 tal ends of the spicula. With them a median piece extends along the spicula 

 and appears to end opposite the body-axis, near the base of the apophysis. The 

 karyokinesis of the sperm atocytes shows the arrangement of the chromosomes 

 in spireme threads, something very uncommon in nemas. 

 Habitat: Larat, East Indies. Marine Fig. 79, p. 299. 



XI. Order Triplonchia. 



80. Triplonchium cylindricum n. sp. Cuticle naked as in the case of nearly 



6.9 13. "'541" 98. a ^ Triplonchs. 



, 3.i 37a T IT 1-2 " Cylindroid neck 



7.6 15. "-M 97. ending in a con- 



*ni' in "nm '"X ^ HUB 'Bfliu /m - 3 ' 4 4 ~ 4 ' 2 ~' 7 ' " vex - conoid head - 



*jy \\ Amphids more or less protrusile, projecting con- 

 mnd siderably in all specimens killed with Flemming's 

 solution. (See illustration.) In some respects 

 the amphids are reminiscent of those of certain 

 Mermithidae. Oesophagus mainly cylindroid, 

 but finally expanding to form a pyriform bulb 

 nearly two-thirds as wide as the base of the neck, 

 and having a rather indistinct valve one-sixth as 

 wide as itself. The lining of the oesophagus is 

 lot a very distinct feature. There is no very 

 distinct cardia. The intestine becomes at once 

 about two-thirds as wide as the body. The cells 

 contain numerous refractive spherical granules, the largest of which are about 

 one-sixth as wide as the body, the smallest of which are very much smaller. 

 These granules are packed so closely together as to obscure the details of the 

 histological structure of the intestine. Anus continuous; rectum slightly refrac- 

 tive. The lateral fields have not been clearly seen, but appear to be about one- 

 fourth as wide as the body. Renette unknown. The nerve-ring surrounds the 

 oesophagus squarely, and there are numerous nerve cells close together, both in 

 front of the nerve-ring and behind it, filling the greater part of the cavity of the 

 neck. From the slightly raised vulva the distinctly cutinized vagina leads back- 

 ward a distance nearly equal to half the corresponding body diameter; it then 

 joins the single uterus, which extends first backward, then forward. This latter, 

 when empty, appears to be about two-fifths as wide as the body. The end of 

 the posterior ovary lies about one to two body-widths behind the vulva. Noth- 

 ing is known concerning the size and form of the eggs. There is a cell located 

 about as far behind the base of the neck as this latter is behind the anterior 

 extremity, which attracts attention on account of its somewhat peculiar appear- 

 ance. It presses the intestine to one side, and has a distinct nucleus, with a 



