HA RD WICKE' S SCIENCE- G OS SIP. 



125 



towards the circumference. The similarity of this 

 arrangement to the muscles in the iris of the eye is 

 very suggestive. The inner ring contracting would 

 close the orifice, the short bars contracting would 

 dilate it. This arrangement of fibres acts here as a 

 sucker by which Trichodina attaches itself to its host, 

 and by which it can detach itself. We understand 

 how it is that the little guest keeps its hold in spite 

 of the movements of its host. 



Trichodina, then, is an example of one of the 

 higher Infusoria, and, although belonging to the 

 lowest sub-kingdoms, it still is developed perhaps as 



Fig. Z4.— Trichodina mitra. a, side view ; b, underview ; 

 c, Planaria covered with trichodina. 



highly as a single cell can be. We must, however, 

 bear in mind that differentiation in function is not the 

 same as differentiation in structure, and that, although 

 certain parts of the protoplasm of Trichodina have 

 certain functions, the structure may be microscopically 

 the same. One part, indeed, may have a mixed 

 function ; thus, although one part is "muscular," it 

 may also, to some extent, be " nervous " as regards 

 function. It is of course understood that here in a 

 unicellular organism, muscular structure or nervous 

 structure is an impossibility. 



In conclusion : the little organism that is the 

 subject of this paper is only one of the many in- 

 teresting members of this group. It has some near 

 relatives which attach themslves to other organisms ; 

 some to other species of Planaria, and one, I believe, 

 to Hydra. Its more distant relatives are numerous, 

 and include Vorticella and its allies. 



Bernard Thomas. 



SOLWAY DUNES IN APRIL. 

 By the Rev. Hilderic Friend, F.L.S., Carlisle. 

 T the embouchure of the river Eden, some twenty 



A 



miles west of Carlisle, situate on the Solway 

 Coast, is the quiet little watering-place known as 

 Silloth. The air is remarkably charged with ozone, 

 and as the soil is composed of sand, the heaviest 

 rainfall does not make the air damp for any lengthy 

 period. During the summer months Silloth is a 



favourite resort for the quiet-seekers and health- 

 seekers of Carlisle, and even in the early months of the 

 year a few invalids, who cannot get farther south, 

 find the place congenial if the east wind is not blowing. 

 Naturalists are not superabundant here, and we never 

 hear of their quarrelling because they are so numerous 

 that there is not prey enough for each to share in 

 Nature's spoils. Were they plentiful, it is certain 

 that the banks of the Solway would soon have little 

 that is new to reward them for their pains, but a 

 solitary worker, to whom nothing comes amiss, may 

 find even in this barren spot enough to occupy all the 

 little time he can snatch for a holiday during the 

 sunny days of April. It may interest some of the 

 readers of this journal if I put together a few notes 

 which I have made here between April 5th and I2th, 

 and which fairly represent the work to be done by 

 the naturalist, unless he be sportsman or fisherman 

 as well. Of ornithology and of dredging I have 

 nothing now to say. 



Landing at the station, the stranger finds himself 

 surrounded by sand-dunes. In front of the little 

 town much of the sand has been levelled down, and 

 is now bound together by the roots of the common 

 sand-sedge (C. arenaria, L.), which is the only carex 

 to be found in any quantity here. Farther away the 

 sand is kept together by quantities of sand-grass or 

 marram, and these two plants are predominant features 

 in the flora. Just now we may find the following 

 plants in bloom on the dunes or in the damp ditches 

 close by :— The celandine (with its cluster-cup, 

 ^cidium ficaria), ladies'-smock (C. pratensis, L.), 

 with the hirsute and flexuous species of bitter-cress,, 

 the tiny whitlow grass, flowering by the thousand on 

 the short turf, the whole plant not an inch high, the 

 common chickweed, red dead nettle, gorse, thale- 

 cress (S. Thalianuni), daisy, colt's-foot, scurvy-grass 

 (C danica), and a few other common forms. 

 Plunging through the sand we hope to find something 

 on the water-mark, and at once begin to turn over 

 the materials left by the receding tide. Among the 

 alg.-e we find nothing rare. Long lines of brownish- 

 green or greenish-brown matter tell us of the fate of 

 hundreds of plants of serrate and common bladder- 

 wrack {Fitciis serratus and F. vesiculosus), which are- 

 intermixed with the fronds of Halidrys, whose air- 

 bladders are so attractive a feature in this form of 

 seaweed. When you have mentioned Laminaria and. 

 Corda, the green Ulva latissitna, a couple of the 

 floridese and the pretty coralline, the list of marine 

 algre found on the Solway is nearly exhausted. Other 

 stragglers of course are found now and again, but as 

 they are all dead or dying, they can seldom be obtained 

 in a good state for preservation. Most of those which 

 I have mentioned, however, may be found growing 

 near the harbour. 



Somewhat disappointed, we turn our attention 

 next to the minuter forms of life around us, and soon 

 discover that there is a good deal to interest us here. 



