258 Mr. G. B. Sovverby on Mulleria. 



Species 4. 



Scissurella elegans, testa ovali, ventricosa, spira. papilliformi, 

 elevatiuscula ; anfractibus quatuor, costis transversis, minus pro- 

 niinentibus, distantibus, longitudinaliter striatis.* 



Found with the last. These two species are very rarely entire, 

 on account of their extreme brittleness. Length two millim. 



Shell oval, ventricose, fragile, spire nipple-shaped, less de- 

 pressed than in the other species ; volutions four, with transverse 

 slightly salient ribs, distant from each other, and each marked 

 with superficial longitudinal striae, which give the shell a finely 

 decussated appearance : the space between the two edges of the 

 obliterated part of the slit is smooth, and narrower in this than in 

 the preceding species : around the umbilicus is seen a smooth 

 space, instead of the circular lines remarkable in the first three 

 species : the aperture is rounded, and the peristome sharp-edged. + 



Art. XXXVII. MULLERIA, a new Genus of Fresh- 

 water Bivalves, of the Family of Ostreacea?, established by 

 M. Lb Baron d'Audebard de Ferussac. 



We do not intend here to give the characters of this genus, 

 because we reserve most of the particulars relating to it for an 

 opportunity, which will shortly occur, of illustrating them by a 

 plate : we only wish at present to notice the addition of a genus 



* I have been obliged to alter some of the expressions used by the author, 

 because in his description of this species he has used several terms of compari- 

 son with the other species; thus I have used " elevatiuscula" instead of " moins 

 deprime que celui des autres e'speces." 



+ The shortness of the time now before us, renders it impossible to add the 

 description of one or two other species which I possess : these I propose giving 

 in the next number; together with the descriptions of several other curious little 

 fossils found in the Fossil Sand of the neighbourhood of Paris, and some further 

 observations upon the Scissurella 1 . 



