14 MR. H. ADAMS ON NEW SHELLS. [Jan. 9, 



incrassato, expansiusculo, marginibus callo crasso junctis, dex- 

 tro suhsinuato. 

 Long. 15, diam. 4 mill. ; ap. 4 mill, longa, 3 lata. 

 Hah. Mauritius. 



This species was received with the name palangula attached to it. 

 But the true j)alangula is, according toM. Morelet, who has had an 

 opportunity of seeing that species in Ferussac's collection, the same 

 as teres, Pfr. I have therefore considered it necessary to describe it 

 as new. 



Fam. Galeommid^. 



Genus Thyreopsis, H. Ad. 



Testa cequivalvis, cequilateralis, triyono-ovata, aperta ; margine 

 dorsali convexo, ad nmbones subacuto. Cardo edentulus, liga- 

 mento interna sub umbonibus instructus. 



Thyreopsis coralliophila, H. Ad. (PI. IV. figs. 8, 8 a.) 



T. testa solidiuscula, subpurpurea, ad margines pallidiore ; super- 

 Jicie valvarum concentrice striata, marginibus dorsalibus pau- 

 luni elevatis, ritgosis ; umbonibus parvis, Icevibus, approximatis. 



Long. 10, alt. 4 mill. 



Hab. Mauritius. 



In this singular genus the valves are always vridely separated ; and 

 when they most nearly approach one another, the shell may be likened 

 to a depressed Emarginiila cut through the centre lengthways. It 

 appears to have more affinity with Libratula, Pease, than with Ga- 

 leomma, but differs so much from the former as to render it desirable 

 to constitute a new genus to receive it. Mr. Nevill informs me that 

 it was found alive by his friend Dr. Power on a coral-reef at Mauri- 

 tius, and that the animal could barely enter the shell. It would 

 appear to be parasitic upon the coral, which is also probably the 

 case with Libratula, as Mr. Pease states that he found that genus 

 living on coral. In Libratula the animal does not extend beyond 

 the shell. 



Note. — In a former paper read by me on new species of Mauritian 

 Shells, some observations on the animals by Mr. G. Nevill were ap- 

 pended to the descriptions, in which the expression "mantle" should 

 correctly have been written " foot," and " foot" should have been 



"sole of foot." 



Descriptious of some New Species of Land and Marine 



Shells. By Henry Adams^ F.L.S. 



(Plate IV.) 



Macrochlamys tenuicula, H. Ad, (PI. IV. fig. 9.) 



M. testa aperte perforata, turhinata, tenui, sublcevigata, levissime 

 apiraliter striatida, rufo-cornea, diaphana, nitida ; spira con- 



