VENERUPIS. 87 



to the anterior end, so that the posterior dorsal margin occupies 

 nearly one side of a parallelogram : heal:s small, inflected, and 

 inclining considerably to the anterior side : ligament yellowish- 

 brown or horncoloiir, contained in a groove or excavation 

 with shelving sides, which extends for some distance from the 

 beaks: hinge-line obtuse-angled: hinge-plate thick and broad: 

 teeth erect, placed on the anterior dorsal line, the outermost 

 and innermost diverging ; in the right valve 3, of which the 

 outside one is much smaller than the other two, and these are 

 cloven ; in the left valve are also 3 similarly arranged, the 

 innermost being the smallest : inside porcellanous, often par- 

 tially stained with reddish -brown, particularly the hinge-plate 

 and posterior side : pallial scar uneven, with a tongue-shaped 

 sinus : muscular scars deep ; anterior roundish, posterior oval 

 and situate close to the margin at the lower angle. L. 0*5. 

 B. 1. 



Habitat : Laminarian zone on the coasts of Dorset^ 

 Devon^ Cornw^aH Glamorgan, Pembroke, and Ireland 

 (west, south, and east). Red Crag (S.Wood); and 

 Philippi has recorded it from the South-Italian tertiaries. 

 It has not been noticed in Scotland or further north; 

 its southern distribution extends from Brittany to the 

 Adriatic, Black Sea, and JE^eaii, both sides of the 

 Mediterranean, and the Canary Isles, at depths ranging 

 from the shore to 20 f. 



It is attached by a byssus to gneissic rocks in Con- 

 nemara (Farran), and to the roots oi Laminaria bulbosa 

 in the west of Ireland (Harvey) ; it occupies holes made 

 by Saxicava rugosa in new-red sandstone at Exmouth 

 (Clark), in limestone at Tenby (J. G. J.), and Cannes 

 (Mace) ; and it inhabits crevices of rocks (but never 

 perforates them) on the coast of Sicily (Philippi) . The 

 shell being frequently distorted shows that the Venerupis 

 is not a borer, but accommodates itself to any place of 

 shelter : when thus enclosed it is occasionally incrusted 

 with nullipore and Spirorbis granulatus. The very 

 young are square, and the fry nearly circular. In perfect 



