4 Transactions of the Society. 



high on the back, and that it has a curious trefoil opening. In 

 one of the specimens I could distinctly see several spermatozoa 

 attached to the ovary and still moving. The spermatozoa were of 

 two shapes — or at all events along with the usual spindle-like forma 

 were others like a curved cord with a puckered ribbon sewn all 

 down it. Both these forms can be readily seen in the sperm sacs 

 of the males, and both are constantly in motion. How the sper- 

 matozoa got outside of the ovary I cannot imagine — and that some 

 were outside I am certain. The ovary, I believe, opens into the 

 anus, and I know of no way in which the spermatozoa could 

 escape into the perivisceral cavity. 



There is a point of resemblance between Conochihis and the 

 Floscules which is well worth notice. From the mastax to the 

 mouth the alimentary canal is strengthened in an unusual way by 

 a tube much harder than the surrounding parts. In Floscularia 

 campanulata the tube hangs down from the mouth, and is con- 

 stantly thrown into long slow undulations. As it is transparent, 

 its edges only can be usually brought into focus, so that it looks 

 like two waving lines or like the edges of two flat membranes, iind 

 thus it has been described. Under favourable circumstances, how- 

 ever, food or water may be seen to dilate it as it passes down, and 

 I have repeatedly seen this happen in such a way as to make it 

 obvious that the structure is really a tube. On crushing F. cam- 

 panulata or Conochilus volvox, the tube will be found to remain, 

 and even to resist the action of caustic potash along with the harder 

 portions of the mastax. 



Notommata aurita. — A few months ago I found this rotifer in 

 great abundance in a pond near Bath. The water was swarming 

 at the same time with free Vorticellae of a fine dark green, speckled 

 with brown. The bottle that I carried home with me had a very 

 large number of these restless creatures in it, and I found them 

 very much in my way as I was examining the Notommata, for they 

 constantly knocked up against the rotifers, and made them with- 

 draw the curious earlike apjiendages from which they derive their 

 name, and which I was anxious to see. One thing puzzled me 

 very much, and that was the rapid disappearance of the Vorticellae 

 from the bottle. The surface of the water was alive with them 

 when I brought them home, and next morning there were not a 

 fourth of the number to be seen. Almost all the Notommata, too, 

 were useless for purposes of observation, for they were gorged with 

 green food, so that their stomachs hid the other organs. The exact 

 similarity of tint between the contents of the Vorticellae and the 

 stomachs of the Notommata had already struck my attention, when 

 I thought I saw a rotifer (unluckily on the opposite side of a bit of 

 horn-wort) holding one of the Vorticellae. Could it be possible 

 that these Notommata could eat the Vorticellae? I put a large 



