USES OF THE DEM AN IAN BECEET1ON 



437 



Oncholaims having the demanian system, 

 at least most of them, have a way of collecting 

 together in masses when artificially assembled 

 in sea water. Conceivably this habit may 

 have some connection with the demanian 

 secretion, but it is not obvious why only adult 

 females should secrete for this purpose alone. 



The demanian system appears more dis- 

 tended when the uterus is full or nearly full of 

 eggs. For instance, at this time the uterine 

 efferent and portions of the uterus of pristiurus 

 may contain an abundance of colorless, trans- 

 parent, rather structureless-looking matter, 

 resembling, under the microscope, partially, 

 dissolved shavings of gelatin. 



The question arises as to what becomes of the 

 secretion of the accessory gland of the male, Fi g- 8 - Profile of head end of male 

 which is possibly or probably a homologue of ^S^2?^Si 



the demanian system in the female. No reply } eft ventral submedian is the 

 . , . , , . longest, see on dsl and on subm 



to this question has occurred in connection (#). The sensilla and amphidial 



with these investigations except that the "gum nery e are shown. Nuclei shown 

 ,.,., . , . .. ,. mostly central nervous system; 



arabic-like" mixture seen in the uterus of the scattered darker ones are. 



pristiurus might possibly have been derived o^lei of the lateral chord, the 



_, . , , ,, , ,, , , , width of which is pointed out 



wholly or in part from the male. It should & tchrdlat. 



perhaps be mentioned that 



X350 



Fig. 9. Tail, male Oncholaimium 

 appendiculatum. ppl, single ven- 

 tral papilla; del (3), caudal ducts 

 leading to spinneret; appndl, 

 ventral, erectile appendicule; an 

 set, anal setae ; set subm (12), sub- 

 median setae on male only. 



in the nemic 



genus Rhab ditis, glands accessory to the 

 male gonad are known that secrete a copu- 

 latory cement; but no such cement is yet 

 known in connection with any oncholaim. 



Of course, the mere presence of this 

 material in the uterus and in the portion of 

 the uterine efferent nearby does not of 

 itself indicate the direction of the flow, but 

 the structure of the organs distinctly sug- 

 gests that the flow is caudad, i.e. from the 

 uterus toward the external openings near 

 the tail. Were the entire flow of the deman- 

 ian system toward the uterus, it would 

 seem strangely circuitous. 



While the fact that no external exit 

 pores have been discovered in Oncholaimium 

 appendiculatum makes conceivable a flow 

 from its enteric vessel and the moniliform 

 glands through the uvette to the uterus, yet 

 the structure of the uvette pore seems as dis- 

 tinctly adapted to a flow in the opposite 



