214 Proposed new Ge?ms of Univalve Shells, 



extent, similar. This is particularly remarkable in the pairs 

 of complementary angles before spoken of, one of which oc- 

 curred at the commencement (Dec. 11. to Dec. 16.), and the 

 other a short time before the close (from Jan. 3. to Jan. 7.). 

 The dotted line in fig. 20. 2. exhibits the symmetrical nature 

 of the connecting curve between November and December. 



It now remains for me to offer a few remarks on the 

 probable utility of arranging observations of the wind in a 

 similar manner. It is evident, from an inspection of the 

 figures, that, during the above-mentioned months, the vari- 

 ations of the wind were such as to form well-marked curves ; 

 and, from observations made at other periods, I am inclined 

 to believe that distinct curves are continually being described 

 by the anemonal movements ; so that, when a particular curve 

 is commenced, the variations of the wind will be in accord- 

 ance therewith until it is closed. An extensive collection of 

 such curves would afford facilities for ascertaining under what 

 peculiar circumstances similar curves occur ; and a careful 

 comparison of such curves with each other, and the curves 

 generally with the barometrical, thermometrical, and hygro- 

 metrical changes of the same periods, could not fail of increas- 

 ing our stock of data in that most interesting and, at the same 

 time, difficult branch of natural history, meteorology. 



Art. X. On Cyprcecdssis, a proposed )ieiv Genus of Univalve Shells, 

 for the Reception of certain Species of Brugiere's Genus Cas- 

 sis. By Samuel Stutchbury, Esq., A.L.S., Curator of the 

 Bristol Institution, &c. 



CYPRiECA'sSIS. 



Shell, when young, striated, reticulated, or tuberculated ; 

 outer lip simple: when mature, outer lip involute, and toothed ; 

 columella lip also toothed ; aperture straight, anteriorly ter- 

 minated by a recurved canal, posteriorly by a shallow channel. 

 Animal with the mantle bilobed ; operculum none. 



The above genus has hitherto been confounded with Cassis, 

 and, in the form of their shells, a considerable analogy cer- 

 tainly exists ; but it will be found that these genera differ in 

 the following important characters : — The true Cassides 

 possess no operculum ; and the animal, by means of its 

 mantle, completes the mouth in the young shells, at each 

 separate period of growth, as perfectly as in the most mature ; 

 protecting the upper portion of the shell by an epidermis : 

 while, on the contrary, the genus before us never forms or 



