32 



iu its trauspareut aud beautiful shell. The cilia just referred to 

 are large and powerful, and the young Doris is enabled to move 

 rapidly through the water. In time, however, the ciliary appara- 

 tus gradually disappears, and the animal has to content itself with 

 slower modes of progression, either crawling among seaweeds aud 

 occasionally displaying to some delighted natui'alist, as he gazes 

 into the clear water of a shore pool, tin exquisitely beautiful 

 rosette which forms the breathing apparatus it carries on its back, 

 comiug to the surface and reversing its position, it will convert its 

 large concave " foot" into a boat, and so swim away back down- 

 wards. 



JUNE. 



Mr. J. Fidlagar described and exhihited a new Rotifer found upon 

 the water 2)lant, Riccia Fluitans. 



I have had for a long time some of the Riccia Fluitans (a crypto- 

 gram) in one of my vases, some of which are decayed, and the 

 chlorophyl, or colouring matter, had left the vegetable tissues quite 

 clear and transparent. On placing some of the decayed weed under 

 the microscope on January 21 of this year, I observed in it some 

 round bodies of an amber colour, which soon became oval in shape, 

 the contents of which were seen to move and turn half round and 

 back again, a motion often seen in the interior of many rotifers, 

 aud in the ovum of many small animals, and I thought that proba- 

 bly these same round and oval bodies were eggs, which they ulti- 

 mately proved to be. In course of time the round body of the egg, 

 became oval aud more egg- shaped, aud in about three hours, from 

 the small end of the egg, a sort of tube or shaft gradually pro- 

 truded, and displayed a row of rather long vibratile cilia rotating 

 on the top ; the tube was quite as long as the oval shaped body, 

 telescopic in its form, and could be withdrawn into the body. The 

 jaws were placed at the bottom of the tube, and were plainly 

 seen in action. When alarmed the creature would quickly with- 

 draw the wheel of cilia and the tube also ; then it would protrude 

 first a sort of horn, and sometimes two, as a .«ort of feeler, previous to 

 again displaying the wheel of cilia. These rotifers appear to be 

 lodged in the cellular lissucs of the plant, and at times they 

 protrude their tube through the cells of the plant. The rotifers are 

 very small ; I made them out to be only 7-1000 of an inch in length. 

 I tried to isolate one of them and to get it clear of the decayed 

 vegetable matter in which the creature was imbedded ; but this was 

 a troublesome thing to effect, and 1 lost several in the attempt. 

 The telescopic nature of the tube is very plainly seen either in the 

 act of protrusion or retraction. At limes the tubes will withdraw, 

 and remain in a state of rest for five or six hours, and be then again 

 put forth with the ciliated lobes, and continue to rotate for the same 



