Jfew South Wales. 



161- 



a tvvo-i)arted. sexual system — consisting of a vaj^iua, two uteri, and two 

 ovaries, — which grows to such an extent as finally to occupy tlie greater 

 part of the body. The complete history of its development I have not 

 yet been able to follow, simply from lack of time. 1 think it presents 

 no unusual diilicultics. At the same time that the sexual organs are grow- 

 ing so vigorously other parts of the organism are pursuing an opposite 

 course. As already pointed out, the anus disappears at the first or second 

 moult. Soon all of that portion of the elementary canal behind the oesopha- 

 gus undergoes a degeneration and disappears. The spear and oesophagua 

 alone remain intact. The muscular layer lining the cuticula also disinte- 

 grates. We have, as the result of this growth on the one hand and 

 degeneration on the other, a sac consisting of the cuticula of tlie worm, 

 almost comjdetely filled with a two-parted egg-producing api)aratus, and 

 supplied with nourishment by means of powerful sucking-organs. 



If now wo turn our attention to the development of the male we find 

 a very different history. No one would have ventured to predict such a 

 remarkable series of changes as we have now to follow. A parallel rase is 

 known but for a single animal species, the closely allied Heterodera {Tylen- 

 clius) Schachlii, 8chmidt. As before remarked, up to the stage represented 

 in Fig. 3, tlie sexes are with difficulty distinguished from each other. But 

 thereafter the history of the male is totally different from tiiat of the female. 

 If the larva shown in Kg. 3 be a male, its next moult 

 gives rise to a slender worm of the form shown in I, 

 Fig G. This remarkable moulting condition is showr. in 

 III. Fig 0, where the slender young male is represented 

 as several times coiled inside its former skin of very dif- 

 ferent shape. By its constant activity it at last succeeds 

 in rupturing the old skin — not, however, before it has 

 again moulted — and issues a distinct male with all the 

 sexual organs complete. 



In this condition, which is the adult male state, measure- 

 ments give the following formula: ^'; ';^ ."' " ^'^ 1-33 mm., 

 in which 88 is the measurement to the centre of the 

 median bulb, inasmuch as I have not been able to satisfy 

 myself as to the exact position occupied by the nerve- 

 ring. The cuticula, like tliat of the female, is devoid 

 of hairs and presents about five hundred transverse 

 strise. The conoid neck terminates ni a truncated head 

 bearing no cephalic seta;, but armed with six distinct, 

 rather hemispherical or conoid lips. 1 could discover on 

 the only two specimens examined no papilhe. lateral 

 organs or eye-spots. The spear is rather stout for its 

 length, being, no doubt, a very effective organ. That 

 portion of the opso])hagus in front of the powerful pro- 

 late or ellipsoidal median bulb is one-fourth ;is wide as 

 the neck and is lined with tiiick, glistening, chitinous 

 walls. The median bulb itself is two-thirds as wide as 

 the adjacent part of the neck and also presents a 

 chitinous lining in the form of a central apparatus one- 

 fifth as wide as the bulb and of the same form. The 

 intestine is at least two-thirdM as wide as the body and 

 its cells are jiackcd with fine granules ; it tcrminales 

 posteriorly in a rectum twice as long as the anal diame- 

 ter. The tail is obliquely hemispherical-conoid and 



Fia. 6— Male of Oaii;- 

 WORM (T. arenaHvt), 

 I. mature male, x 65 ; 

 II, head of same, x 460: 

 in, larval male, inside of 

 its cast off skin, X 50; 

 IV and V, cross and lon- 

 Kitndinal sections, x SBO; 

 VI. lateral and veutnd 

 view of tail, x 22S : >, 

 spear ; h, bulb."* ; i, intcs* 

 tine ; az, spermatozoa ; r, 

 cuticula : V, vas deferens; 

 rf, end of ductus ojacula- 

 torius ; ps, penes or spi- 

 cida ; a, anus. 



