EMARGINULA, 



WG have figured, which approach very near to Blainville's 

 Parmophorus in shape: another objection may arise from 

 the apparent want of the anterior fissure in Parmophorus, 

 but it will be seen that the anterior edge of the shell is 

 always somewhat emarginate, while in the situation of 

 the branchiae, the anterior fissure in the mantle of the 

 animal, and in the position of the vertex in the shell, 

 they exactly resemble each other; we, therefore, consider 

 the Pttrmophori of Blaiiiville and Lamarck, as elongated 

 and compressed -Em^rg-w^w/^^. 



Shell clypeiform, or depressedly conical, 'more or less 

 oblong, hollow beneath; vertex turned backwards; an- 

 terior margin slit or notched. Anterior sides of the 

 muscular impression interrupted, expanded, not continued 

 across the front. 



Emarginula, even including the Parmophoriy is not a 

 numerous Genus; though much more so than it appears 

 to be in Lamarck : the recent species are found in the 

 seas of almost all climates: one or perhaps two are 

 inhabitants of our own coasts. Some of them are very 

 pretty little shells. The Parmophorus is the same as 

 the Scutum of Montfort, and the Patella ambigua of Chem- 

 nitz ; and in England, is commonly called the Duck*s Bill 

 Limpet ; it is not a common shell. 



The fossil Emarginulae are scarce : they occur in the 

 Calcaire grossier, and its contemporary strata; in the 

 Crag of Sufiblk, Essex, and Norfolk; and in the Bath 

 Oolite : they are very elegant little fossils, particularly 

 Lamarck's E. clypeata. We cannot consider his Parmo- 

 phorus elongatus as a species ot this Genus, for its verte^c 

 is anterior, as its muscular impression demonstrates! 

 consequently, we find in it no mark of a canal at either 

 jend : it must therefore be classed with Patella. 



Our plate represents at 



JFig. 1. Emarginula elongata^ Parmophorus elongatus, Blainv. 



2. hrevicula, '■ — breviculus, Blainv, 



3. fismrata. Patella fissurata, Chemn, 



4. elegans. A fossil species, from Normandy. 



5. reticulata., Patella reticulata, Chemn. 



p, , . tricostata. tricostata. Humph, 



I 



