298 110 



walzenförmiger, zurùckziebarer und am Ende bewimperter Penis gelegen. Verdauungskana 

 feht; anstatt desselben ist ein grosser, birnförmiger Hoden entwickelt. 

 Size: Male 400—600//, female 1300—2000. 



Melicerta conifera Hudson. 



Hudson-Gosse 1889, p. 72. 



Gosse in Hudson-Gosse (1889, p. 72, PI. D, fig. 6) supposes 



that he has seen the male; but the figure and description are so sketchy that they have only 

 very slight scientific value. 



Melicerta janus Huds. 



Hudson-Gosse 1889, p. 75. 



HuDsox-GossE (1889, p. 75) writes: 



"Mr. Hood tells me that he has seen the male, and that it resembles that which I have 

 figured as the male of M. tubicolaria." 



Melicerta tubicolaria Ehrbg. 



Hudson-Gosse 1889, p. 73. 



HuDSON-GossE (1889, p. 73, PI. 5, fig. 3 c). Hudson supposes 



that he has seen the male. "The nervous ganglion, spermsack and penis were plainly visible, 

 and I could see the motion of the spermatozoa, though not the individual spermatozoa them- 

 selves; neither could I make out the muscles nor the water vascular sj'stem." 



Tbe Melicerta colonies, especially tbose of M. ringens, but also those of M. janus, 

 are ven,' common in our ponds. Curiously enough I have never bad tbe good luck 

 to observe tbe males. 



General remarks. 



It will be seen that we possess only a limited knowledge of the males of Co- 

 nochilus volvox, Lacinularia socialis and Melicerta ringens. The males are alv\'ays small 

 often only about 50 /< ; that of L. socialis 2 — 300 // : conesbaped without any con- 

 spicuous foot, but often with a cupsbaped body, a sucker in wbicb tbe foot glands 

 debouch. Tbe wbeel-organ is a single ciliary wreath, encircling a disc, wbicb is 

 commonly cone-shaped, cairv-ing two eyes, provided with lenses. A large brain; most 

 probably always a dorsal and two ventral antennæ, but they bave not always been 

 observed. No mastax and often no trace of alimentary canal at all. Lateral canals 

 with vibra tile tags not always detected, but perhaps always present; no contractile 

 vesicle. A large pyriform testis, a cilia-covered ductus seminalis, no real penis but 

 the ductus seminalis may be partly tiu-ned inside out; large masses of oil globules. 

 Muscular system insufficiently known; many transversal muscle bands seem to be 

 a rule. Tbe males are extreme!}' active animals and very variable in form. 



Microcodonidæ. 



Tbe family comprises tbe two genera Microcodon and Microcodides. The males 

 are almost unknown. 



