78 



Miscellaneous, 



is a very peculiar one, a strong rapid current running over a gravelly 

 bottom : in such exposed situation our Unios do not often attempt 

 a lodgement, but prefer sandy bars or muddy shores where the water 

 is not very deep or rapid. Upon these gravel beds, however, the 

 large shells are imbedded, and the young ones spin the byssus by 

 which they attach themselves to the larger shells or the stones of 

 the gravel. In this way I have seen hundreds moored and riding se- 

 curely at anchor at the utmost tension of their lines ; for it is only, 

 as far as I can perceive, a single filament. The thread appears to be 

 attached to the mantle, and is probably produced by it, and is not an 

 umbilical attachment. I saved some of the animals in spirits." — 

 Letter, 16th May, 1840. 



This account is curious in several particulars ; first, as showing 

 the relations of these animals to the family of Arcades ; second, as 

 showing what I have long expected from the observations I have 

 made on some marine gasteropodous mollusca, — that many, if not 

 most of the kinds, have the power of forming a byssus when it can 

 assist them in their habits. It is very desirable, however, that the 

 place where the byssus is attached to the animal should be re- 

 examined, for if it takes its origin from the mantle, it is an ano- 

 maly in the organization of mollusca. It always arises, as far as I 

 am aware, from some part of the foot, in general from the anterior 

 part of the base, as in Mytilus, Pinna, Avicula, Pecten, &c, but some- 

 times from the end of this organ, as in Area, from whence also, I 

 should suspect, it most probably arises in the Uniones. — J. E. Gray. 



ON SOME RECENTLY PROPOSED GENERA OF THE PIFERR1DJE, 



To the Editors of the Annals and Magazine of Natural History. 



Gentlemen, — You did me the honour of reprinting in your ' Annals 

 of Natural History' for March, 1840, a short paper on the Crania and 

 Dentition of the Carnivora, which I communicated to the Zoological 

 Society. My object, as stated in that paper, was merely to point out 

 a few simple characters by which the groups might be distinguished, 

 the importance of those characters being confirmed by others exhi- 

 bited, both by the internal anatomy and externa^ structure of the spe- 

 cies. Since the publication of that paper, M. Isidore Geoffroy* has 

 furnished us with figures and descriptions of some interesting ge- 

 nera of Carnivora from Africa and Madagascar, which, according to 

 my views, should be added to those already included in my list of 

 the Viverridce. They consist of the genera Ichneumia, Galidia, and 

 Galidictis. The first of these (Ichneumia) belongs to that subdivision 

 of the Viverridce in which there is a complete bony orbit, and is 

 founded upon three species described originally as species of the ge- 

 nus Herpestes or Ichneumon. The other two genera {Galidia and 

 Galidictis\) , in the straightness of the lower margin of the rami of 



* See the ' Magazin de Zoologie* of M. F. E. Guerin-Meneville, Parts 

 9 and 10 for 1839. An extract of this paper appeared in the * Comtes 

 Bendus,' &c. for October, 1837. 



f In the original paper Galictis. The alteration in the name was neces- 

 sary, Mr. Bell having given the name Galictis to a group of the Mustelidce. 



