104 



BA RD WICKK S SCIENCE- G OSSIP. 



was afterwards confirmed by Mr. Taylor at Ealing, 

 who saw two bright lines in the spectrum of R. Leonis 

 and one bright line in that of R. Hydrse. 



In May, Mercury is a morning star, and will be in 

 a good position for observation after sunset towards 

 the end of the month. 



Venus is a morning star during the whole of the 

 month. 



Mars is an evening star near Aldebaran in the 

 middle of the month, 



Jupiter is not well situated for observation. 



Saturn is in Leo, and may be observed after sunset. 



There will be no celestial phenomena of unusual 

 interest this month. 



semi-parasitic state on the water wood-louse [Asellus' 

 vulgaris). Four of these rotifers I found just in the 

 central line, between the legs of the asellus, arranged 

 in order, the front of each one to the head of the 

 animal, and overlapping like scales. These never 

 quitted their situation, and, what made it certain 

 that they were in permanent quarters on their host, 

 among the feet of the rotifers, but not attached in 

 any way, there were three eggs, glued on to the body 

 of the asellus. One rotifer was on the side of the, 

 animal, and three others were swimming in the water, 

 which they did in a graceful manner, not very 

 quickly, but with ease, turning the foot from side to 

 side, then coming to anchor and making their 

 sucker a pivot, swimming round and round, but soon. 



l\^^iililll!^ 



Fig. 76. 



Fig- 77- 



Fig. 78. 



Fig. 79. — Front view. 



Fig. 80.— Side view. 



SOME LITTLE-KNOWN ROTIFERS. 



No. I.— Pterodina truncata. 



By W. Barnett Burn, M.D. 



IN the autumn of 1850, in some water from the 

 Black Sea at Wandsworth (as a piece of water 

 on the Common is called), Mr. Gosse found a single 

 specimen of a rotifer, which he called Pterodina 

 truncata. While looking at it, and as he says, 

 " before my observation had proceeded far," he was 

 called away ; on his return it was retracted, and it 

 soon died. He never saw it again, and, I believe, it 

 has not been again recognised till I found it in 

 November, 1888, in a shallow pool on Tooting 

 Common, which is about three-quarters of a mile 

 from where it was originally discovered. 



Tke reason of it so seldom coming to notice is 

 probably due to its habitat. It appears to live in a 



moving off again, as if they had not " brought up '* 

 in the place they desired. On being frightened, foot 

 and head disappeared with great rapidity. Tapping 

 on the side of the stage was sufficient to effect this. 

 The way in which the long foot shot up through the 

 opening in the lorica was very striking. This rotifer 

 is the most like a Brachionus in the genus Pterodina,. 

 being much thicker than the others, as the side view 

 will show. Moreover, the organs go more to the 

 edges, as there is greater room there than in the 

 other species, and, partly in consequence, it is not so 

 transparent. 



Mr. Gosse says the eyes are small and transparent, 

 but he figures them of a moderate size and red, and 

 such I find them. In the animal when closed the 

 edge is not everted as in Mr. Gosse's figure, but as ia 

 Fig. 79. The occipital margin is thrown into a fold, 

 and the pectoral has a slit. When the head pro- 



