The Structure of the Annelids. 365 



latitudes, and, secondly, its whiteness helps to conceal the 

 animal when traversing the snow. 



In nearly every book on arctic travel the white fox is referred 

 to, and its habits described. Pennant tells us " that in Spitz- 

 bergen and Greenland, where the ground is entirely frozen, 

 they live in the clefts of rocks, two or three inhabiting the 

 same hole. They swim well, and often cross from island to 

 island in search of prey." The Grreenlanders trap them either 

 in pitfalls dug in the snow and baited with fish, or in an in- 

 genious kind of spring trap constructed of " whalebone." 



Sir John Richardson informs us that the arctic fox appears 

 to be wanting in that extreme cunning for which reynard in 

 general is so celebrated ; ' ' they will stand by whilst the trap 

 is being prepared for them, and walk straight into it as soon 

 as the hunter has left it." 



It is an open question whether or not the ' ' blue fox " is a 

 species distinct from the white, or only a different condition of 

 age ; and as I am not prepared with any facts likely to settle the 

 matter one way or the other, I shall not attempt to enter upon 

 any discussion concerning it. There were only about ninety- 

 two skins offered at the March sales, for the year 1866. 



THE STRUCTURE OF THE ANNELIDS, WITH A 

 CRITICISM ON QUATREFAGES. 



By Edouard Claparede. 



(Continued from page 273.) 



Respiratory Apparatus. — "M. Quatrefages has actually 

 made science retrograde in respect to the structure of the 

 organs of respiration of Annelids. This is the weakest part 

 of his book, alike in the introduction and in the generaliza- 

 tions concerning each family. The branchise have, according 

 to the opinion of the honourable academician, a special struc- 

 ture, which permits them always to be distinguished. " These 

 organs," he "says, "are characterized by a single canal, to 

 and from which the afferent and efferent vessels run. This 

 canal, of which the walls are sometimes visible, and at others 

 indistinct, is surrounded by a diahhanous substance, which 

 appears to result from a thickening of the dermis. In this 

 substance ampulla-shaped lacunae are hollowed out, more or 

 less developed, and always destitute of proper walls. The 

 whole is surrounded by an epidermis extremely fine, and 



