Insects. 537 



crossed by others at right angles : but under a very high power these cross fibres are 

 no longer seen, and each fibre appears to be composed of a cylinder, so formed as to 

 present more or less transparent markings at regular distances from each other, giving 

 a transversely striated appearance. These striae are apparently produced by an ana- 

 logous method to those on the primary fasciculus of muscle, and there is but little 

 doubt of the contractile nature of this arrangement, inasmuch as it assists in the open- 

 ing of the shell when the ligament is behind the hinge, which otherwise could never 

 be effected. Mr. Quekett concluded with various observations on the mode of action 

 of these different structures, and on the astonishing power exhibited by the peculiar 

 arrangement of the structure of the external ligament in opening valves of immense 

 weight, as in Chama Gigas, whose shells frequently weigh as much as one hundred 

 weight. — J. W. 



Notice of c A Systematic Catalogue of British Land and Fresh-wa- 

 ter Shells ; for labelling Collections, 8$c. : containing all the 

 Species hitherto discovered in Great Britain and Ireland? Lou 

 don : Simpkin, Marshall & Co., Stationers 1 Hall Court. York: 

 John L. Linney. 1844. 



We beg to recommend this useful little catalogue to those who are 

 interested in our native shells: its objects and plan will be best ex- 

 plained by quoting the author's preface. 



" A systematic list of British Land and Fresh-water Shells for the purpose of la- 

 belling collections, or serving as a medium by which collectors may show their desi- 

 derata, has been long needed ; and although the following catalogue may be objected 

 to by many, as not containing the Marine Shells, it will, it is hoped, prove useful to 

 those who are engaged in the study of this beautiful branch of our British Conchology. 



" The arrangement of the genera and species, as well as the nomenclature, is with 

 some exceptions the same as that adopted in Mr. Gray's edition of ' Turton's Manu- 

 al.' A short list is added of those shells which have been admitted on insufficient 

 grounds, or which are supposed to be varieties of other species. Limneus liueatus of 

 Bean, and L. acutus of Jeffreys, have been found about Scarborough, by Mr. Bean, 

 whose indefatigable researches in Natural History are so well known. 



" We have heard of one specimen of Achatina octona being taken in Ireland, but 

 think its existence as a British species requires further proof. 



" Some of the numerous varieties of Anodon Cygneus, should, it is thought, be 

 more justly regarded as species ; and we believe this class would amply repay careful 

 investigation." 



Notes on the habits of Thyridopteryx Ephemeraformis, (Stephens). 

 By P. H. Gosse, Esq. 



The following notes on the habits of an American Lepidopterous 

 insect may be deemed not uninteresting. On the 6th of September, 

 ii M 



