82 The Irish Naturalist . [April, 



"scallop." Its symmetrical form and beautiful fan-shaped 

 markings led to its use in decorative art from an earl}- period, 

 and it served in the middle ages as a badge for pilgrims to the 

 Holy Land, whence originated Pecten Jacobceus, "St. James's 

 shell." The hinge-line extends beyond the beaks on either 

 side, forming the so-called "ears," one of which is generally 

 notched beneath for the passage of the byssus. Aviculopccten, 

 whose dual name implies resemblance on the one hand to the 

 earlier form, Aviaila, and on the other to Pecte?i, belongs to a 

 large group of smooth, or elegantly ornamented shells, the 

 latter generally having radiate sculpture as in the modern 

 shell. Colour-bands are sometimes preserved in these 

 shells, such markings being met with more frequently among 

 fossil shells than is probably commonly supposed. Avicnlo- 

 pccteu is tolerably abundant in the Carboniferous Limestone 

 of this country. 



Cardiomorpha and Cc?wcardiuvi have both a certain likeness 

 to the cockle-shell of our shores, hence the word Cardium 

 ("heart," or "cockle-shell") appropriately enters into the 

 structure of their names. In the first of these the position of 

 the beaks, almost overhanging the anterior end of the shell is 

 a characteristic feature. It is a common shell in the lime- 

 stone quarries. Conocardium is distinguished by a long, 

 shell} 7 , spine-like process, said to have served as a sheath for 

 the siphons, projecting from the posterior end of the shell, or 

 what is, on this hypothesis, held to be such. Without much 

 care the spine gets broken off and left in the rock, from which 

 it is difficult to extract it. The shell is often beautifully and 

 delicately sculptured. Very large specimens have been 

 obtained, usually much crushed, in the rock ledges on the 

 shore between Malahide and Portmarnock in the County of 

 Dublin. The best preserved specimens have been collected 

 in the County of Limerick ; a fine series of them is to be seen 

 in the Museum of Science and Art, Dublin. 



Among the Gastropoda Euomphalus is very characteristic, 

 abundant, and usually well preserved, its arched construction 

 and rather thick and smooth shell greatly favouring the 

 operation of removing the rock from it. Its neatly coiled 

 shell recalls Planorbis, the "pond-snail," but its whorls have 

 angular, not rounded, margins, and they form on the under 

 side of the spire an unusually deep, funnel-shaped cavity, the 



