36 FRESHWATER LIFE. 



cast along with it ; and, floating on the water, preser\-es the eggs through 

 the cold season, till they are hatched hy the retiu-niug warmth of spring. 



In July, 1870, I found in a shallow pool on the turfy soil of Lindow 

 Common, Cheshire, a good many examples of one of the Daphnia family, 

 which, from its long bristles, bears the name of Macnithrix. My speci- 

 mens corresponded to Baird's description, except that a particular bristle 

 mentioned by him was wanting in my capture. I had possibly chanced 

 upon a new variety. The superior antennas ai'e of considerable size, 

 hanging from the beak like two flat swords, with a broad, straight-edged 

 extremity. While watching an example in the live-box, what was my 

 astonishment to observe some of the parts suddenly become doiible. 

 One after the other, the hinder segment, its hooked spines, the beak, 

 superior antenna?, and so on, appeared double ; and it became evident 

 that I was the fortunate witness of the moulting process. I at once 

 mounted the whole aftair in glycerine, and my Macrothrix now lies side 

 by side with its cast-off skin. 



One other family of the Cladocera should be mentioned, if only because 

 it contains CItydorus si^Jucricus, a very common species in our stagnant 

 ponds. The I jI/ nee idee (for so the family is called) may be recognised by 

 a black spot situated in front of the eye, and looking not much unlike a 

 second eye, which, however, it is not. The intestine, moreover, makes 

 one complete turn aiid a half. To the same family belong iMnjrorus 

 lamellatttx and Acropcrus liarpce, both of which occur in this neighbour- 

 hood. The latter is fond of resting on the top of the water, moored by 

 its antennas to a bit of weed ; or a cluster of them wall collect round 

 some floating leaf or sprig, and lie motionless in the warm sunshine as if 

 asleep. 



Of the last order, Phyllopoda, we shall cite only one example, 

 Cheirocephahia diapliannx, or the Fairy Shrimp. I have not yet seen it 

 alive, but those who have speak with enthusiasm of its singular beauty. 

 The male is especially gorgeous. With regard to anatomy, the body is 

 destitute of a carapace, and is divided into many segments, affording 

 gi'eat freedoin of movement. The male has a remarkable pair of inferior 

 antennfe, employed essentially as clasping organs. Those of the female 

 are simpler, being shaped like a broad sickle. There are two stalked 

 eyes, each composed of an immense number of lenses, showing a further 

 advance towards the insect typo. Its young, however, has but one simple 

 eye, placed centrally in front of the head. This is represented in the 

 adult by a dark blind spot. No fewer than eleven segments compose the 

 thorax, to each of which is attached a pair of branchial feet, of a broad 

 and leaf -like form. The tail consists of two broad appendages ; and both 

 feet and tail are thickly besot with plumose hairs. Extending from the 

 head to near the tail may be discerned about eighteen or nineteen small 

 hearts, or quasi-hearts, placed end to end and all moving together. The 

 female possesses a single external ovary, fi'om which, at the proper time, 

 from 100 to 400 eggs are jerked out in succession during twenty-four 

 hours. When hatched the young undergo a scries of moultings and 

 changes of fonn before they Anally resemble their parent. 



We have now completed our illustrations of Freshwater Entomos- 

 traca. I shall not at present enter into any desciiption of the marine 

 kinds. Specimens of their empty carajiaces, particulai-ly of the 

 Ostracoda, may be found in the sand of our coasts, and will often occur 

 to the searcher after foraminifera. I have thus obtained examples of 

 Vytheri'ix and CytJwrr. I have also taken, near Peumaenmawr, a good 

 many Cetochilus, a rather strildng form resembling Cyclops. 



The Entomostraca have played an important part in the life-history 

 of the globe from the earliest epoch to the most recent. Thoj' have been 



