AtfATINA. 147 



very similar hinge and dentition, have satisfied us of the 

 family identity. Though, in our only specimen of the "fer- 

 ruginosa" the moveable ossicle is not present, probably in 

 consequence of its being removed with the animal, still we are 

 convinced that in perfect and fresh specimens, opened with 

 great care, the ossicle will be found ; the delicacy and fragility 

 of this appendage are excessive, and though we have several of 

 the A. bidentata in beautiful condition, ninety-nine out of a 

 hundred cabinet examples will be found imperfect. Conse- 

 quently being morally certain that the " ferruginosa " has the 

 " shibboleth " of the Anatina, we feel justified in consigning it 

 to that family, to range with its congener the A. bidentata. 



We cannot concur with Mr. Alder in recognizing that his 

 Montacuta ferruginosa exhibits a connective gradation with 

 Kellia, Lepton, and Galeomma. We think these genera are 

 well distinguished not only from it, but from each other, and 

 are absolutely of different family types. We hope our new 

 locations and explanatory remarks on these genera will satisfy 

 naturalists that every discordance exists between Lepton and 

 Galeomma, with the "ferruginosa "; the strict Arcadan foot 

 of the first two has no community with the common lingui- 

 form pedal appendage of the latter, and all the other organs 

 of one and the other are equally heterogeneous ; and lastly, 

 we state, that the differences between Kellia and the "ferru- 

 ginosa " are equally decisive. 



To prevent repetition, we only give short notes and refer- 

 ences to the four remaining species of this family. 



A. DECLIVIS, Pennant et nobis. 



Thracia pubescens, Brit, Moll. i. p. 226, pi. 16. f. 2, 3. 

 Anatina myalls, Lamarck. 



This is the largest British Anatma, being sometimes 

 3 inches transverse, and 2 of vertical measure. It differs in 

 no essential point from its congeners except in size. It is a 

 rare species, and it is difficult to obtain a suite of examples 

 from half an inch upwards. It is taken in the coral zone at 

 Exmouth, but rarely alive, 



L2 



